Tooth preparation guide device and method of preparing tooth for dental prosthesis

ABSTRACT

Dental preparation uses a tooth preparation guide custom-made for fitting with teeth of a patient. The preparation guide includes one or more guide channels for guiding a cutting tool. The preparation guide enables modification of the teeth as planned with high level of precision. A dental prosthesis for installing onto prepared teeth of the patient is provided before preparation of the teeth. The prosthesis includes features that are complementary to the prepared teeth. The prosthesis can be installed immediately after preparing the teeth using the preparation guide. With the high level of accuracy and precision in the preparation of teeth, no modification of the prosthesis would be needed for installation.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims the priority to Korean Patent ApplicationNo. 10-2010-0114678, filed Nov. 17, 2010, Korean Patent Application No.10-2011-0065074, filed Jun. 30, 2011, Korean Patent Application No.10-2011-0077930, filed Aug. 4, 2011, U.S. Patent Application No.61/503,572, filed Jun. 30, 2011, U.S. Patent Application No. 61/503,580,filed Jun. 30, 2011, International Patent Application No.PCT/US11/61090, filed Nov. 16, 2011, contents of which are herebyincorporated herein by reference in their entirety.

BACKGROUND

1. Field

The present application relates to dental restorations, and moreparticularly to systems, devices, and procedures for dentalrestorations.

2. Related Technology

A crown and bridge is a main example of dental restorations forrestoring a missing or damaged tooth. When a crown and bridge prosthesisis chosen for restoring a missing tooth, the two adjacent teeth of themissing tooth are modified (cut) and prepared. Then, a copy of the toothpreparation is made by taking an impression of the oral configurationincluding the missing tooth and modified teeth. The copy is sent to adental lab for the construction of a desired prosthesis. The preparationof the adjacent teeth typically exposes internal structures of the teethincluding dentin and/or pulp tissues. Since fabricating the prosthesistakes some time, e.g., a period of one to three weeks, in order to coverand protect the exposed portions, typically a temporary prosthesis canbe made and installed. Once the desired prosthesis is received from thedental lab, the temporary prosthesis is removed, and the prosthesis isplaced over and cemented to the abutments, i.e., the prepared adjacentteeth.

In modifying and preparing teeth, once cutting is done in natural teeth,it is not reversible. When cutting is excessive, dentin and pulp tissuescan be damaged. The preparation of teeth, particularly the amount cut orprecision of cut, heavily depends on the hand skills and experience ofthe dentist. Presently there appears no technology that practicallyreplaces hand skills and experience of dentists. Also, there appears notechnology that significantly improves hand skills of dentists andsignificantly reduces the risk of possible inaccuracies of dentists.

The foregoing discussion is to provide background information of theinvention and does not constitute an admission of prior art.

SUMMARY

Among many others, the present invention provides the following featuresand characteristics.

In one aspect of the invention, a dental preparation guide deviceincludes a guide channel that guides a cutting tool to cut two or moreteeth in one traveling of the guide channel.

In one aspect of the invention, a dental preparation guide deviceincludes a guide channel for making a horse shoe shaped or similarlyshaped groove into a lingual side of an anterior tooth. A dentalprosthesis having a horse shoe shaped or similarly shaped protrusionthat is fitting into the groove of the anterior tooth. The surfaces ofthe groove and protrusion are shaped and aligned with an axis at highprecision so that the prosthesis and prepared tooth are engaged onlywhen the prosthesis approaches the anterior tooth in the particular axis(of insertion) at substantially high accuracy.

In one aspect of the invention, a dental preparation guide deviceincludes a guide channel with two or more sections, each of which isconfigured to fit only with a predetermined and specially shaped cuttingtool.

In one aspect of the invention, a method of dental preparation includescutting one or more teeth using a single preparation guide device with aguide channel, in which one cutting tool is used in a portion of theguide channel and another cutting tool is used in another portion of theguide channel.

In one aspect of the invention, a dental preparation guide deviceincludes multiple guide channels, each of which is designed to cut oneor more teeth.

In one aspect of the invention, a method of dental preparation includescutting multiple teeth using a single preparation guide device.

In one aspect of the invention, a method of digital dentistry procedureincludes determining an axis of insertion of a dental prosthesis toinsert into or engage with a prepared tooth. The method includes tiltinga 3D image of a tooth to check the size, magnitude and/or amount ofundercut portions or areas and identifying a particular axis oforientation of the 3D image, in which the size, magnitude and/or amountof the undercut portions or areas are minimized or acceptable for adental prosthesis. A computer program includes algorithms and processsteps to conduct this method.

In one aspect of the invention, a dental preparation guide deviceincludes a single body with a cutting-tool guide channel and a lumpprojecting or protruding from the single body like a peninsula, in whicha cutting tool entrance is provided.

In one aspect of the invention, a dental preparation guide deviceincludes a guide channel for guiding a cutting tool and an entrance ofthe guide channel through which the cutting tool enters into the guidechannel, wherein the device includes a stopper or stopping feature,which stops the cutting tool at a proper level for sliding into theguide channel.

In one aspect of the invention, a dental preparation guide deviceincludes a guide channel for guiding a cutting tool and an entrance ofthe guide channel through which the cutting tool enters into the guidechannel, wherein the guide channel includes a non-cutting section fromthe entrance to a point in the guide channel where cutting of a toothbegins, wherein in the non-cutting section the cutting tool is only totravel along the section without cutting the tooth.

In one aspect of the invention, a dental preparation guide deviceincludes a guide channel for guiding a cutting tool and an entrance ofthe guide channel through which the cutting tool enters into the guidechannel, wherein the entrance is located very close to a point in theguide channel where cutting of a tooth begins, whereby no non-cuttingsection is not needed, wherein in the non-cutting section the cuttingtool is only to travel along the section without cutting the tooth.

In one aspect of the invention, a dental preparation guide deviceincludes a marking indicative of directions for using the preparationguide device.

In one aspect of the invention, an elongated dental cutting toolincludes a cutting portion in the elongated body and a non-cutting tipstepped from the cutting portion.

In one aspect of the invention, a method of dental preparation using adental preparation guide and an elongated dental cutting tool, whichincludes a cutting portion in the elongated body and a non-cutting tipstepped from the cutting portion. The method includes running thecutting tool to cut a tooth while the cutting tool is engaged with thedental preparation guide, wherein the cutting portion cuts the tooth andthe non-cutting tip contacts and abuts un-cut surface of the tooth,which prevents the cutting tool (non-cutting tip) from tilting in adirection toward the un-cut surface of the tooth.

In one aspect of the invention, an elongated cutting tool includesconfigurations, features or structures for engaging with a guide channelof a dental preparation guide device. The dental preparation guidedevice also includes complementary or counter-part configurations,features and structures to accommodate those of the cutting tool. Theengagement of the tool with the preparation guide device prevents orminimizes tilting of the cutting tool while the tool is engaged with theguide channel.

In one aspect of the invention, a dental preparation guide deviceincludes a guide channel for cutting an occlusal surface of a tooth andalso another guide channel for cutting a side surface of the same tooth.

In one aspect of the invention, a method of dental preparation includespreparing a tooth using a dental preparation guide device which includesa guide channel for cutting an occlusal surface of a tooth and alsoanother guide channel for cutting a side surface of the same tooth.

In one aspect of the invention, a dental preparation guide deviceincludes a single body configured to be placed over a group of teethincluding an open space (missing tooth) interposed by a first tooth anda second tooth. The preparation guide device includes a first guidechannel for cutting the first tooth and a second guide channel forcutting the second tooth.

In one aspect of the invention, a dental preparation guide deviceincludes a single body configured to be placed over a group of teeththat do not include a missing tooth. The preparation guide deviceincludes multiple guide channels, each of which is for cutting one toothof the group.

A method of dental restoration includes: identifying a group of teeththat are in need of splinting and do not include a missing tooth;providing a dental preparation guide device that is custom-designed forthe group of teeth; placing the dental preparation guide device over thegroup of teeth and engaging the same with the teeth; preparing (cutting)each of the group of teeth using the preparation guide device; providinga dental prosthesis having features configured to fit each of theprepared teeth; fixing the dental prosthesis to the group of teeth.

In one aspect of the invention, patients are allowed to view images ofprospective prostheses and choose a desired one even before thepreparation of a tooth for the prosthesis.

In one aspect of the invention, a dental preparation guide deviceincludes a guide channel (guide way) that guides a cutting tool to cutthree or more side surfaces of a tooth in one traveling of the guidechannel.

In one aspect of the invention, a method of dental preparation includescutting three or more side surfaces of a tooth using a single guidechannel of a dental preparation guide device.

In one aspect of the invention, a method of dental preparation includescutting two or more teeth using a single guide channel of a dentalpreparation guide device.

In one aspect of the invention, a dental restoration kit includes adental preparation guide device configured to fit at least one tooth andto cut the at least one tooth. The dental restoration kit furtherincludes a dental prosthesis custom-made in view of a desiredpreparation of the at least one tooth using the dental preparation guidedevice. The dental restoration kit further includes at least one cuttingtool that is designed to engage with a guide channel of the dentalpreparation guide and to travel along the guide channel. The dentalrestoration kit may further includes a cement for bonding the dentalprosthesis onto the at least one tooth after the desired preparation.

One aspect of the present invention provides a method of providing adental restoration kit, the method comprising: providing a first 3Dimage data representing one or more teeth of a patient before a desiredpreparation of the one or more teeth for installing a desired dentalprosthesis; before the desired preparation and before making the desireddental prosthesis, determining an axis of insertion along which thedesired dental prosthesis should approach the one or more teeth forengaging the desired dental prosthesis with the one or more teeth afterthe desired preparation, wherein the axis of insertion is determinedrelative to the one or more teeth; generating a second 3D image datarepresenting the one or more teeth after the desired preparation;producing a preparation guide device based on the first 3D image dataand the second 3D image data, wherein the preparation guide device isproduced as a single piece device that comprises an interior spaceconfigured to receive the one or more teeth for engagement therewith andfurther comprises at least one guide channel configured to guide a burrfor cutting at least part of the one or more teeth for the desiredpreparation; and producing the desired prosthesis based on the first 3Dimage data and the second 3D image data.

In the foregoing method, determining the axis of insertion may comprise:processing the first 3D image data to orient a 3D image of the one ormore teeth in multiple directions; providing information of undercuts inmultiple directions of orientation of the 3D image; and choosing adirection of orientation of the 3D image as the axis of insertion basedon the information of the undercuts. Generating the second 3D image datamay comprise processing the first 3D image data with the input of anarea of cutting and depth of cutting. Generating the second 3D imagedata may comprise processing the first 3D image data with the input ofone or more selected from the group consisting of an orientation of theburr, a diameter of the burr, a length of the burr, tapered shapeinformation of the burr, a position of the burr relative to the one ormore teeth, a distance between a rotational axis of the burr and anexterior surface of the one or more teeth, and a level of the burrrelative to the one or more teeth. Producing the desired prosthesis maycomprise: generating a fourth 3D image data of the desired prosthesis;and making the desired prosthesis using the fourth 3D image data. Themethod may further comprise providing the burr.

Another aspect of the invention provides a method of making devices fordental procedure, comprising: providing a first 3D image datarepresenting one or more teeth of a patient before a desired preparationof the one or more teeth for installing a desired dental prosthesis;before the desired preparation, generating a first image illustrating afirst prospective shape of the one or more teeth that would exist afterinstallation of a first dental prosthesis; before the desiredpreparation, providing the first image for the patient's review of thefirst image; subsequent to the patient's approval of the first image andbefore the desired preparation, making the first dental prosthesis basedon the first image; and subsequent to the patient's approval of theimage, making a preparation guide device based on the first 3D imagedata, wherein the preparation guide device is custom-made to fit atleast part of the one or more teeth and comprises at least one guidechannel configured to guide a burr to cut the one or more teeth forfitting the first dental prosthesis without the need of additionalsubstantial cutting of the one or more teeth.

In the foregoing method, the method may further comprise: before thedesired preparation, generating a second 3D image data representing aprospective, prepared shape of the one or more teeth that would existafter the desired preparation thereof. The method may further comprise:before the desired preparation, generating a second image illustrating asecond prospective shape of the one or more teeth that would exist afterinstallation of a second dental prosthesis; before the desiredpreparation, providing a plurality of images comprising the first andsecond images for the patient's review; and receiving the patient'sapproval of the first image rather than the second image, wherein thefirst and second prospective shapes differ in at least one selected fromthe group consisting of length, width, surface curvature, embrasure andshading.

Still in the foregoing method, the method may further comprise:subsequent to providing the first image and prior to the patient'sapproval, receiving the patient's request to modify the first image;changing the first prospective shape based on the patient's request tomodify the first image; and providing an modified first imageillustrating the changed first prospective shape for the patient'sapproval.

Still another aspect of the invention provides a method of dentalprocedure, comprising: making a first dental prosthesis and apreparation guide device in accordance with the foregoing method; andproviding the first dental prosthesis and the preparation guide deviceto a dental practitioner for preparing the one or more teeth andinstalling the first dental prosthesis onto the one or more teeth afterpreparation.

In the foregoing method, the method may further comprising providing theburr along with the first dental prosthesis and the preparation guidedevice, wherein the preparation guide device further comprises a guidegroove formed along the at least one guide channel, wherein the burrcomprises an elongated body with a bump between two ends thereof,wherein the elongated body is configured to fit in the at least oneguide channel of the preparation guide device and the bump is configuredto fit the guide groove such that the guide channel and the guide groovein combination position and orient the burr relative to the one or moreteeth in a predetermined manner.

Yet another aspect of the invention provides a method of dentalprocedure, comprising: providing a dental prosthesis for installing ontoone or more teeth of a patient, the one or more teeth comprising a firsttooth comprising an occlusal surface and buccal, a lingual, distal andmesial sides; providing a preparation guide device in a single piece foruse in preparing the one or more teeth of the patient for installing thedental prosthesis, wherein the preparation guide device is custom-madeto fit at least part of the one or more teeth and comprises at least oneguide channel configured to guide a cutting tool, wherein the at leastone guide channel comprises a first single channel that the cutting toolcan travel through without having to remove the cutting tool from thepreparation guide device; mounting the preparation guide device over theone or more teeth such that the preparation guide device fit the atleast part of the one or more teeth; and cutting the first tooth withuse of a burr as the cutting tool by moving the burr through the firstsingle channel configured to cut the first tooth on three or four of thebuccal, lingual, distal and mesial sides without having to remove theburr from the preparation guide device, which completes preparation ofthe first tooth for installing the dental prosthesis onto the firsttooth without the need of an additional preparation guide for preparingthe first tooth and without the need of an additional substantialcutting of the first tooth; and installing the dental prosthesis ontothe first tooth so as to surround the three or four of the buccal,lingual, distal and mesial sides of the first tooth.

In the foregoing method, cutting of the three or four sides may leave atleast a portion of the four sides uncut, wherein the uncut portioncomprises a contact point of the first tooth that contacts a neighboringtooth. The first single channel may be configured to cut the four of thebuccal, lingual, distal and mesial sides, wherein cutting of the foursides entirely encircles the first tooth when viewing in a directiontoward the occlusal surface, wherein the dental prosthesis comprises aring structure contacting the four sides of the first tooth that are cutusing the first single channel. The first single channel may beconfigured to cut the four of the buccal, lingual, distal and mesialsides, wherein cutting of the four sides does not entirely encircle thefirst tooth and leaves at least part of one of the four sides uncut whenviewing in a direction toward the occlusal surface, wherein the dentalprosthesis comprises a C-shaped structure contacting the four sides ofthe first tooth that are cut using the first single channel.

Still in the foregoing method, the one or more teeth may comprise afirst tooth and a second tooth, wherein cutting the one or more teethcomprises cutting the first tooth and then cutting the second tooth,wherein the preparation guide device is not disconnected from the one ormore teeth between cutting the first tooth and cutting the second tooth,and wherein the first single channel is further configured to cut thesecond tooth in addition to cutting the first tooth without having toremove the burr from the first single channel. The one or, more teethmay comprise a first tooth and a second tooth, wherein cutting the oneor more teeth comprises cutting the first tooth and then cutting thesecond tooth, wherein the preparation guide device is not disconnectedfrom the one or more teeth between cutting the first tooth and cuttingthe second tooth, and wherein the at least one channel comprises asecond single channel that is distinct from the first single channel andconfigured to cut the second tooth. Providing the dental prosthesis maycomprise receiving the dental prosthesis from a third party or makingthe dental prosthesis in-house, wherein providing the preparation guidedevice comprises receiving the preparation guide device from a thirdparty or making the preparation guide device in-house.

Yet in the foregoing method, the method may further comprise: causing toprovide a 3D image data representing the one or more teeth of thepatient before preparation sufficient to install the dental prosthesis,wherein causing to provide the 3D image data comprises at least oneselected from the group consisting of: scanning of the patient's oralfeatures using a 3D scanning device; taking an impression of thepatient's oral features; producing a 3D model of the patient's oralfeatures from the impression; and scanning the 3D model using a 3Dscanning device.

A further aspect of the invention provides a dental preparation guideapparatus in a single body, the single body apparatus comprising alingual sidewall, a buccal sidewall opposing the lingual sidewall, andan occlusal wall interconnecting the lingual and buccal sidewalls toform the single body, wherein the lingual sidewall, the buccal sidewalland the occlusal wall in combination define an interior space in whichto receive a tooth comprising a buccal surface, a lingual surface, amesial surface, a distal surface and an occlusal surface such that thelingual surface faces the lingual sidewall, the buccal surface faces thebuccal sidewall, and the occlusal surface faces the occlusal wall,wherein the single body comprises a guide channel formed in the occlusalwall and shaped to receive with a cutting tool to guide the cutting toolto travel along a trajectory; wherein the guide channel comprises abuccal section, a lingual section, and an interconnecting sectioninterconnecting the buccal and lingual sections to provide the guidechannel as a single integrated channel that allows the cutting tool totravel through the guide channel without being removed therefrom; andwherein when viewing in a direction toward the occlusal wall, the buccalsection extends generally along the buccal sidewall, and the lingualsection extends generally along the lingual sidewall.

In the foregoing apparatus, the buccal section may be configured to havea portion of the cutting tool enter into the interior space and betweenthe buccal sidewall and the tooth such that the portion of the cuttingtool cuts at least part of the buccal surface while traveling in thebuccal section; wherein the lingual section is configured to have theportion of the cutting tool enter into the interior space and betweenthe lingual sidewall and the tooth such that the portion of the cuttingtool cut at least part of the lingual surface while traveling in thelingual section; and wherein the interconnecting section is configuredto have the portion of the cutting tool enter into the interior spaceand between the tooth and an immediately neighboring tooth such that theportion of the cutting tool cut at least part of the mesial or distalsurface while traveling in the interconnecting section. When viewing inthe direction toward the occlusal wall, a tangential line of the buccalsection at a point thereof may be parallel to a tangential line of thelingual section at a point thereof. The guide channel further maycomprise a second interconnecting section that further interconnects thebuccal and lingual sections to provide the guide channel in the form ofa closed loop when viewing in the direction toward the occlusal wall.The guide channel may further comprise another section extending fromeither the buccal section or the lingual section, wherein when viewingin the direction toward the occlusal wall, a tangential line of theother section at a point thereof is parallel to a tangential line of theinterconnecting section at a point thereof.

Still in the foregoing apparatus, the guide channel may further compriseanother section extending from either the buccal section or the lingualsection, wherein when viewing in the direction toward the occlusal wall,a tangential line of the other section at a point thereof is parallel toa tangential line of the interconnecting section at a point thereof,wherein the other section does not interconnect between the buccal andlingual sections to make the guide channel in the form of a closed loop.The guide channel may be configured to have the cutting tool passthrough the occlusal wall such that the cutting tool extends into theinterior space, such that the cutting tool cuts the buccal surface whenthe cutting tool travels in the buccal section and such that the cuttingtool cuts one of the mesial and distal surfaces when the cutting tooltravels in the interconnecting section. The interior space defined bythe lingual sidewall, the buccal sidewall and the occlusal wall may beconfigured to receive one or more additional teeth.

One aspect of the invention provides a method of preparing a tooth fordental restoration, the method comprising: providing the foregoingapparatus for preparation of a tooth comprising a buccal surface, alingual surface, a mesial surface, a distal surface and an occlusalsurface; engaging the apparatus with the tooth such that the tooth isreceived in the interior space and such that the lingual surface facesthe lingual sidewall, the buccal surface faces the buccal sidewall, andthe occlusal surface faces the occlusal wall; inserting a burr as thecutting tool into the guide channel via an insertion hole; traveling theburr along the trajectory of the guide channel comprising the buccalsection, lingual section and interconnecting section, by which the burrcuts side surface of the tooth comprising at least part of the lingualsurface, at least part of the buccal surface and at least part of themesial or distal surface; and wherein during traveling of the burr alongthe trajectory, the burr is not removed from the guide channel untilcompletion of the cutting side surfaces of the tooth. In the foregoingmethod, when viewing in the direction toward the occlusal wall, atangential line of the buccal section at a point thereof may be parallelto a tangential line of the lingual section at a point thereof.

Another aspect of the invention provides a dental preparation guideapparatus in a single body, the single body apparatus comprising alingual sidewall, a buccal sidewall opposing the lingual sidewall, andan occlusal wall interconnecting the lingual and buccal sidewalls toform the single body, wherein the lingual sidewall, the buccal sidewalland the occlusal wall in combination define an interior space in whichto receive a tooth comprising a buccal surface, a lingual surface, amesial surface, a distal surface and an occlusal surface such that thelingual surface faces the lingual sidewall, the buccal surface faces thebuccal sidewall, and the occlusal surface faces the occlusal wall,wherein the single body comprising a first guide channel formed in theocclusal wall and shaped to engage with a first cutting tool to guidethe first cutting tool to travel along a first trajectory; wherein whenviewing in a direction toward the occlusal wall, the first guide channelcomprising a section that extends generally along at least part of thebuccal sidewall; wherein the single body comprising a second guidechannel formed in at least one of the buccal and lingual sidewalls andshaped to engage with a second cutting tool to guide the second cuttingtool to travel along a second trajectory; and wherein when viewing in adirection toward the buccal sidewall, the second guide channel extendsgenerally along at least part of the occlusal wall.

In the foregoing apparatus, the occlusal wall may comprise an interiorsurface facing the occlusal surface of the tooth when the tooth isreceived in the interior space, wherein the second guide channel extendsgenerally along the interior surface of the occlusal wall when viewingin the direction toward the buccal sidewall; and wherein the buccal sidewall comprises an interior surface facing the buccal surface of thetooth when the tooth is received in the interior space, wherein thefirst guide channel extends generally along the interior surface of thebuccal wall when viewing in the direction toward the occlusal wall. Thefirst guide channel may further comprise another section, which isconfigured to have the cutting tool pass through the occlusal wall suchthat the cutting tool extends into the interior space, and further suchthat the cutting tool cuts one of the mesial and distal surfaces whenthe cutting tool travels in the other section.

A further aspect of the invention provides a method of preparing a toothfor dental restoration, the method comprising: providing the apparatusfor preparation of a tooth comprising a buccal surface, a lingualsurface, a mesial surface, a distal surface and an occlusal surface;engaging the apparatus with the tooth such that the tooth is received inthe interior space and such that the lingual surface faces the lingualsidewall, the buccal surface faces the buccal sidewall, and the occlusalsurface faces the occlusal wall; inserting a burr as the cutting deviceinto the first guide channel of the apparatus, whereby a cutting portionof the burr enters into the interior space and between the buccalsidewall and the tooth; cutting at least part of the buccal surface ofthe tooth while traveling the burr along the first guide channel;inserting the same burr or another burr into the second guide channel,whereby a cutting portion of the burr enters into the interior space andbetween the occlusal wall and the tooth, wherein inserting the same orother burr can occur either before or after cutting the buccal surface;and cutting at least part of the buccal surface of the tooth whiletraveling the same burr or the other burr along the second guidechannel.

One aspect of the invention provides a dental preparation guideapparatus in a single body, the single body apparatus comprising alingual sidewall, a buccal sidewall opposing the lingual sidewall, andan occlusal wall interconnecting the lingual and buccal sidewalls toform the single body, wherein the lingual sidewall, the buccal sidewalland the occlusal wall in combination define an interior space in whichto receive a tooth comprising a buccal surface, a lingual surface, amesial surface, a distal surface and an occlusal surface such that thelingual surface faces the lingual sidewall, the buccal surface faces thebuccal sidewall, and the occlusal surface faces the occlusal wall,wherein the single body comprising a guide channel formed in at leastone of the lingual and buccal sidewalls and shaped to engage with acutting tool to guide the cutting tool along a trajectory; and whereinthe guide channel is configured to have the a portion of the cuttingtool enter into the interior space and between the occlusal wall and thetooth such that the portion of the cutting tool cuts at least part ofthe occlusal surface while traveling in the guide channel.

In the foregoing apparatus, the guide channel may comprises a portconfigured to permit the entry of the cutting tool into the guidechannel, wherein the port of the guide channel is formed through theocclusal wall such that the cutting tool enters into the guide channelformed din the at least one of the lingual and buccal sidewalls via theport through the occlusal wall.

Another aspect of the invention provides a method of preparing a toothfor dental restoration, the method comprising: providing the apparatusfor preparation of a tooth comprising a buccal surface, a lingualsurface, a mesial surface, a distal surface and an occlusal surface;integrating the apparatus with the tooth such that the tooth is receivedin the interior space and such that the lingual surface faces thelingual sidewall, the buccal surface faces the buccal sidewall, and theocclusal surface faces the occlusal wall; engaging the guide channel ofthe apparatus with a burr as the cutting tool, whereby a cutting portionof the burr enters into the interior space and between the occlusal walland the tooth; and traveling the burr along the guide channel whilerunning the burr, thereby cutting at least part of the occlusal surfaceof the tooth.

A further aspect of the invention provides a dental preparation guideapparatus in a single body, the single body apparatus comprising alingual sidewall, a buccal sidewall opposing the lingual sidewall, andan occlusal wall interconnecting the lingual and buccal sidewalls toform the single body, wherein the lingual sidewall, the buccal sidewalland the occlusal wall in combination define an interior space in whichto receive two or more teeth comprising a first tooth and a secondtooth, wherein the lingual sidewall comprises a first lingual sidewalland a second lingual sidewall, the buccal sidewall comprises a firstbuccal sidewall and a second buccal sidewall, the occlusal wallcomprises a first occlusal wall and a second occlusal wall; wherein thefirst lingual sidewall and the first sidewall oppose each other and areconfigured to sandwich the first tooth when the first and second teethare received in the interior space; wherein the second lingual sidewalland the second buccal sidewall oppose each other and are configured tosandwich the second tooth when the first and second teeth are receivedin the interior space; wherein the first occlusal wall is interposedbetween the first lingual sidewall and the first buccal sidewall and isconfigured to overlap the first tooth when the first and second teethare received in the interior space; wherein the second occlusal wall isinterposed between the second lingual sidewall and the second buccalsidewall and is configured to overlap the second tooth when the firstand second teeth are received in the interior space; wherein the singlebody comprises a first guide channel formed in the first occlusal walland shaped to receive a cutting tool to guide the cutting tool along thefirst guide channel; and wherein the single body comprises a secondguide channel formed in the second occlusal wall and shaped to receivethe cutting tool or another cutting tool to guide the same along thesecond guide channel.

In the foregoing apparatus, the first and second teeth may be adjacentwith each other with no tooth therebetween and with no missing tooththerebetween, wherein the first guide channel and the second guidechannel are connected together and form a single connected channel suchthat the cutting tool received in the first guide channel can travel tothe second guide channel without having to be removed from the firstguide channel. The first and second teeth may be immediately next toeach other with each other with no tooth therebetween and with nomissing tooth therebetween, wherein the first guide channel and thesecond guide channel are separate from each other and a portion of thesingle piece body blocks between the first and second channels such thatthe cutting tool received in the first guide channel must be removedfrom the first guide channel in order to be received in the second guidechannel.

Still in the foregoing apparatus, a missing tooth exist between thefirst and second teeth, wherein the lingual sidewall further maycomprise a third lingual sidewall located between the first lingualsidewall and the second lingual sidewall; wherein the buccal sidewallfurther comprises a third buccal sidewall located between the firstbuccal sidewall and the second buccal sidewall; wherein the occlusalwall further comprises a third occlusal wall located between the firstocclusal wall and the second occlusal wall; wherein the third lingualsidewall, the third buccal sidewall and the third occlusal wall at leastpartially surrounds a space of the missing tooth when the first andsecond teeth are received in the interior space. The single body maycomprise a third guide channel formed in the third occlusal wall andshaped to receive the cutting tool or another cutting tool to guide thesame along the third guide channel, wherein the first guide channel andthe second guide channel are connected together via the third guidechannel and form a single connected channel such that the cutting toolreceived in the first guide channel can travel to the second guidechannel without having to be removed from the first guide channel. Thesingle body does not comprises a guide channel in the third occlusalwall, wherein the first guide channel and the second guide channel areseparate from each other and a portion of the third occlusal wall blocksbetween the first and second channels such that the cutting toolreceived in the first guide channel must be removed from the first guidechannel in order to be received in the second guide channel.

Yet in the foregoing apparatus, a third tooth exist between the firstand second teeth, wherein the lingual sidewall further comprises a thirdlingual sidewall located between the first lingual sidewall and thesecond lingual sidewall; wherein the buccal sidewall further comprises athird buccal sidewall located between the first buccal sidewall and thesecond buccal sidewall; wherein the occlusal wall further comprises athird occlusal wall located between the first occlusal wall and thesecond occlusal wall; wherein the third lingual sidewall, the thirdbuccal sidewall and the third occlusal wall at least partially surroundsthe third tooth when the first, second and third teeth are received inthe interior space. The single body may comprise a third guide channelformed in the third occlusal wall and shaped to receive the cutting toolor another cutting tool to guide the same along the third guide channel,wherein the first guide channel and the second guide channel areconnected together via the third guide channel and form a singleconnected channel such that the cutting tool received in the first guidechannel can travel to the second guide channel without having to beremoved from the first guide channel.

Further in the foregoing apparatus, the first guide channel may comprisea first buccal section, a first lingual section, and a firstinterconnecting section interconnecting the first buccal and firstlingual sections to provide the first guide channel as a singleintegrated channel that allows the cutting tool to travel between thefirst lingual section and the first buccal section without having toremove the cutting tool therefrom, wherein when viewing in a directiontoward the occlusal wall, the first buccal section extends generallyalong the first buccal sidewall, and the first lingual section extendsgenerally along the first lingual sidewall. The first buccal section maybe configured to have a portion of the cutting tool enter into theinterior space and between the first buccal sidewall and the first toothfor cutting at least part of a buccal surface of the first tooth whiletraveling in the first buccal section when the first and second teethare received in the interior space; wherein the first lingual section isconfigured to have the portion of the cutting tool enter into theinterior space and between the first lingual sidewall and the tooth forcutting at least part of a lingual surface of the first tooth whiletraveling in the first lingual section when the first and second teethare received in the interior space; and wherein the firstinterconnecting section is configured to have the portion of the cuttingtool enter into the interior space for cutting at least part of a mesialor distal surface of the first tooth while traveling in the firstinterconnecting section when the first and second teeth are received inthe interior space.

In the foregoing apparatus, when viewing in the direction toward theocclusal wall, a tangential line of the first buccal section at a pointthereof may be parallel to a tangential line of the first lingualsection at a point thereof. The first guide channel may further comprisea second interconnecting section that further interconnects the firstbuccal section and the first lingual section to provide the first guidechannel in the form of a closed loop when viewing in the directiontoward the occlusal wall. The first guide channel may further compriseanother section extending from either the first buccal section or thefirst lingual section, wherein when viewing in the direction toward theocclusal wall, a tangential line of the other section at a point thereofis parallel to a tangential line of the first interconnecting section ata point thereof. The first guide channel may further comprise anothersection extending from either the first buccal section or the firstlingual section, wherein when viewing in the direction toward theocclusal wall, a tangential line of the other section at a point thereofis parallel to a tangential line of the first interconnecting section ata point thereof, wherein the other section does not interconnect betweenthe first buccal section and the first lingual section to make the guidechannel in the form of an open loop.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of typical tooth cutting.

FIG. 2 is a perspective view of tooth shape after typical tooth cutting.

FIG. 3 is a perspective view of a preparation guide device in accordancewith one embodiment as mounted on posterior teeth.

FIG. 4 is a perspective view of a preparation guide device and posteriorteeth on which the preparation guide is mounted.

FIG. 5 is a plan view of a preparation guide device mounted on posteriorteeth.

FIG. 6 is a cross-sectional view of a preparation guide device mountedon teeth.

FIG. 7 is a perspective view of a hand piece and a preparation guidedevice mounted on teeth.

FIG. 8 is an enlarged view of a portion of the cutting tool and thepreparation guide device shown in FIG. 7.

FIG. 9 is a cross-sectional view of a cutting tool and a preparationguide device in accordance with one embodiment as mounted on teeth.

FIG. 10 is a perspective view of a preparation guide device inaccordance with one embodiment as mounted on posterior teeth.

FIG. 11 is a cross-sectional view of a preparation guide device mountedon posterior teeth.

FIG. 12 is a perspective view of a preparation guide device inaccordance with one embodiment as mounted on posterior teeth.

FIG. 13 is a perspective view of a preparation guide device inaccordance with one embodiment as mounted on posterior teeth.

FIG. 14 is a perspective view of a preparation guide device inaccordance with one embodiment as mounted on posterior teeth.

FIG. 15 is a perspective view of a preparation guide device inaccordance with one embodiment as mounted on posterior teeth.

FIG. 16 is a perspective view of a preparation guide device inaccordance with one embodiment as mounted on posterior teeth.

FIG. 17 is a perspective view of a preparation guide device inaccordance with one embodiment as mounted on posterior teeth.

FIG. 18A is a perspective view of a preparation guide device inaccordance with one embodiment as mounted on posterior teeth.

FIG. 18B is a perspective view of prepared posterior teeth and a splintprosthesis to be installed on the posterior teeth.

FIG. 18C is a perspective view of the prepared posterior teeth and thesplint prosthesis shown in FIG. 18B as installed on the posterior teeth.

FIG. 19 is a perspective view of a preparation guide device inaccordance with one embodiment as mounted on teeth.

FIG. 20 is a perspective view of a preparation guide device mounted onteeth.

FIG. 21 is a perspective view of a preparation guide device inaccordance with one embodiment as mounted on teeth.

FIG. 22 is a perspective view of preparation guide device in accordancewith one embodiment as mounted on teeth.

FIG. 23A is a perspective view of a preparation guide device inaccordance with one embodiment as mounted on teeth.

FIG. 23B is a perspective view of prepared teeth and a splint prosthesisto be installed on the prepared teeth in accordance with one embodiment.

FIG. 23C is a perspective view of the prepared teeth and the splintprosthesis shown in FIG. 23B as installed on the prepare teeth.

FIG. 23D is a plan view of teeth viewed along an axis of prosthesisinsertion.

FIG. 23E is a cross-sectional view of a groove shown in FIG. 23D.

FIG. 23F is a cross-sectional view of a prepared tooth and a prosthesisto be installed on the prepared tooth.

FIG. 23G is a cross-sectional view of a tooth having an inclinedprospective axis of prosthesis insertion in accordance with oneembodiment.

FIG. 24 is a schematic view of preparing a tooth using a preparationguide device and a cutting tool.

FIG. 25 is a schematic perspective view of a tool guide way and a burrin accordance with one embodiment.

FIG. 26 is a schematic perspective view of a tool guide way and a burrin accordance with one embodiment.

FIGS. 27A and 27B are perspective and cross-sectional views of a toolguide way and a burr in accordance with one embodiment, respectively.

FIGS. 28A and 28B are perspective and cross-sectional views of a toolguide way and a burr in accordance with one embodiment, respectively.

FIGS. 29A and 29B are perspective and cross-sectional views of a toolguide way and a burr in accordance with one embodiment, respectively.

FIGS. 30A and 30B are perspective and cross-sectional views of a toolguide way and a burr in accordance with one embodiment, respectively.

FIGS. 31A and 31B are perspective and cross-sectional views of a toolguide way and a burr in accordance with one embodiment, respectively.

FIGS. 32A and 32B are perspective and cross-sectional views of a toolguide way and a burr in accordance with one embodiment, respectively.

FIGS. 33A and 33B are perspective and cross-sectional views of a toolguide way and a burr in accordance with one embodiment, respectively.

FIGS. 34A and 34B are perspective and cross-sectional views of a toolguide way and a burr in accordance with one embodiment, respectively.

FIGS. 35A and 35B are perspective and cross-sectional views of a toolguide way and a burr in accordance with one embodiment, respectively.

FIGS. 36A and 36B are perspective and cross-sectional views of a toolguide way and a burr in accordance with one embodiment, respectively.

FIG. 36C is a cross-sectional views of a tool guide way and a burr inaccordance with one embodiment.

FIG. 36D is a cross-sectional views of a tool guide way and a burr inaccordance with one embodiment.

FIGS. 37A and 37B are perspective and cross-sectional views of a toolguide way and a burr in accordance with one embodiment, respectively.

FIGS. 38A and 38B are perspective and cross-sectional views of a toolguide way and a burr in accordance with one embodiment, respectively.

FIGS. 39A and 39B are perspective and cross-sectional views of a toolguide way and a burr in accordance with one embodiment, respectively.

FIG. 40 is a schematic perspective view of a tool guide way and a burrin accordance with one embodiment.

FIG. 41 is a schematic perspective view of a tool guide way and a burrin accordance with one embodiment.

FIG. 42 is a schematic perspective view of a tool guide way and a burrin accordance with one embodiment.

FIG. 43 is a cross-sectional view of a cutting tool and a preparationguide device in accordance with one embodiment as mounted on teeth.

FIG. 44 is a perspective view of a preparation guide device inaccordance with one embodiment.

FIG. 45 is a side view of the preparation guide device shown in FIG. 44.

FIG. 46 is another side view of the preparation guide device shown inFIG. 44.

FIG. 47 is a bottom view of the preparation guide device shown in FIG.44.

FIG. 48A is a plan view of the preparation guide device shown in FIG.44.

FIG. 48B is a cross-sectional view taken along a line X-Y shown in FIG.48A.

FIG. 49 is a perspective view of the preparation guide device shown inFIG. 44 as mounted on teeth.

FIG. 50A is another perspective view of the preparation guide deviceshown in FIG. 44 as mounted on teeth.

FIG. 50B is a cross-sectional view taken along a line X-Y shown in FIG.50A.

FIG. 51A is a further perspective view of the preparation guide deviceshown in FIG. 44 as mounted on teeth.

FIG. 51B is a cross-sectional view of the preparation guide devicemounted on teeth taken along a line X-Y shown in FIG. 51A.

FIG. 52 is a plan view of the preparation guide device shown in FIG. 44as mounted on teeth.

FIG. 52A is a cross-sectional view taken along a line AX-Y shown in FIG.52.

FIG. 52B is a cross-sectional view taken along a line BX-Y shown in FIG.52.

FIG. 52C is a cross-sectional view taken along a line CX-Y shown in FIG.52.

FIG. 52D is a cross-sectional view taken along a line DX-Y shown in FIG.52.

FIG. 53 is a perspective view of prepared teeth and a prosthesis inaccordance with one embodiment.

FIG. 54 is a perspective view of a preparation guide device mounted on ateeth in accordance with one embodiment.

FIG. 55A is a further perspective view of a preparation guide device inaccordance with one embodiment as mounted on teeth.

FIG. 55B is a cross-sectional view taken along a plane shown in FIG.51A.

FIG. 56 is a plan view of a preparation guide device in accordance withone embodiment.

FIG. 57 is a perspective view of a preparation guide device inaccordance with one embodiment.

FIG. 58 is a perspective view of the preparation guide shown in FIG. 57as mounted on teeth.

FIG. 59 is a plan view of the preparation guide device shown in FIG. 57.

FIG. 60 is a plan view of the preparation guide device shown in FIG. 57as mounted on teeth.

FIG. 60A is a cross-sectional view taken along line A shown in FIG. 60.

FIG. 60B is a cross-sectional view taken along line B shown in FIG. 60.

FIG. 60C is a cross-sectional view taken along line C shown in FIG. 60.

FIG. 60D is a cross-sectional view taken along line D shown in FIG. 60.

FIG. 61 is a bottom view of the preparation guide device shown in FIG.57.

FIG. 62 is a bottom view of a teeth model and the preparation guidedevice shown in FIG. 57.

FIG. 63 is a perspective view of prepared anterior teeth and aprosthesis to be installed on the prepared anterior teeth in accordancewith one embodiment.

FIG. 64 is a perspective view of prepared anterior teeth and theprosthesis shown in FIG. 63 as installed on the prepared anterior teeth.

FIG. 65 is a perspective view of the prosthesis shown in FIG. 63.

FIG. 66 is a perspective view of a preparation guide device inaccordance with one embodiment as mounted on posterior teeth.

FIG. 67 is a side view of the preparation guide device shown in FIG. 66.

FIG. 68 is a plan view of the preparation guide device shown in FIG. 66.

FIG. 69 is a plan view of the preparation guide device shown in FIG. 66as mounted on teeth.

FIG. 69A is a cross-sectional view taken along line X-YA shown in FIG.69.

FIG. 69B is a cross-sectional view taken along line X-YB shown in FIG.69.

FIG. 70 is a bottom view of the preparation guide device shown in FIG.66.

FIG. 71 is a plan view of prepared teeth and a prosthesis to beinstalled on the prepared teeth.

FIG. 72 is a perspective view of the prepared teeth and the prosthesisshown in FIG. 71.

FIG. 73 is a plan view showing a prepared teeth and a prosthesisinstalled on the prepared teeth.

FIG. 74 is a perspective view of the prepared teeth and the prosthesisshown in FIG. 73.

FIG. 75A is a plan view of a preparation guide device in accordance withone embodiment.

FIG. 75B is a plan view of a preparation guide device in accordance withone embodiment.

FIG. 75C is a plan view of a preparation guide device in accordance withone embodiment.

FIG. 76A is a perspective view of a preparation guide device inaccordance with one embodiment.

FIG. 76B is a cross-sectional view taken along a line X-Y shown in FIG.76A.

FIG. 77A is a plan view of the preparation guide device shown in FIG.76A.

FIG. 77B is a cross-sectional view taken along a line X-Y shown in FIG.77A.

FIG. 78 is a perspective view of prepared anterior teeth and aprosthesis to be installed on the prepared anterior teeth in accordancewith one embodiment.

FIG. 79A is a plan view of a preparation guide device in accordance withone embodiment.

FIG. 79B is a cross-sectional view taken along a line X-Y shown in FIG.79A.

FIG. 80 is a perspective view of a pair of preparation guide devices inaccordance with one embodiment.

FIG. 81A is a perspective view of teeth before preparation.

FIG. 81B is a perspective view of a first preparation guide device shownin FIG. 80 as mounted on teeth.

FIG. 81C is a perspective view of prepared teeth.

FIG. 82A is a plan view of teeth before preparation.

FIG. 82B is a plan view of the first preparation guide device shown inFIG. 80 as mounted on teeth.

FIG. 82C a cross-sectional view taken along an upper line X-Y shown inFIG. 82B.

FIG. 82D is a cross-sectional view taken along an lower line X-Y shownin FIG. 82B.

FIG. 83A is a perspective view of partially prepared teeth.

FIG. 83B is a perspective view of a second preparation guide deviceshown in FIG. 80 as mounted on teeth.

FIG. 83C is a perspective view of fully prepared teeth.

FIG. 84A is a plan view of partially prepared teeth.

FIG. 84B is a plan view of the second preparation guide device shown inFIG. 80 as mounted on teeth.

FIG. 84C a cross-sectional view taken along an upper line X-Y shown inFIG. 84B.

FIG. 84D a cross-sectional view taken along an lower line X-Y shown inFIG. 84B.

FIG. 85 is a plan view of fully prepared teeth.

FIG. 86A is a plan view of a preparation guide device in accordance withone embodiment as mounted on teeth.

FIG. 86B is a cross-sectional view taken along a line X-Y shown in FIG.86A.

FIGS. 87A, 87B and 87C are side views of various burrs in accordancewith embodiments.

FIGS. 88A and 88B are perspective and cross-sectional views of a toolguide way and a burr in accordance with one embodiment, respectively.

FIG. 89 is a plan view of a tool guide way in accordance with oneembodiment.

FIG. 90 is a cross-sectional view taken along a line X-Y shown in FIG.89.

FIG. 91 is a cross-sectional view of a tool guide way in accordance withone embodiment.

FIG. 92A is a side view of a tooth and a burr in accordance with oneembodiment.

FIG. 92B is another side view of a tooth and a burr cutting the tooth inaccordance with one embodiment.

FIG. 92C is a side view of a prepared tooth in accordance with oneembodiment.

FIG. 92D is a view of a prepared tooth and a prosthesis in accordancewith one embodiment.

FIG. 92E is a side view of a tooth and a burr cutting the tooth inaccordance with another embodiment.

FIG. 93A is a plan view of a first one of a pair of preparation guidedevices in accordance with one embodiment.

FIG. 93B is a cross-sectional view taken along a broken line shown inFIG. 93A.

FIG. 94A is a plan view of the first preparation guide device shown inFIG. 93A.

FIG. 94B is a cross-sectional view taken along a broken line shown inFIG. 94A.

FIG. 95A is a plan view of the first preparation guide device shown inFIG. 93A.

FIG. 95B is a cross-sectional view taken along a broken line shown inFIG. 95A.

FIG. 96 is a side view of the first preparation guide device shown inFIG. 93A.

FIG. 97 is another side view of the first preparation guide device shownin FIG. 93A.

FIG. 98A is a plan view of a second one of a pair of preparation guidedevices which pairs with the first preparation guide device shown inFIG. 93A.

FIG. 98B is a cross-sectional view taken along a broken line shown inFIG. 98A.

FIG. 99A is a plan view of the second preparation guide device shown inFIG. 98A.

FIG. 99B is a cross-sectional view taken along a broken line shown inFIG. 99A.

FIG. 100A is a plan view of the second preparation guide device shown inFIG. 98A.

FIG. 100B is a cross-sectional view taken along a broken line shown inFIG. 100A.

FIG. 101 is a side view of the second preparation guide device shown inFIG. 98A.

FIG. 102 is another side view of the second preparation guide deviceshown in FIG. 98A.

FIGS. 103 and 104 are plan and perspective views of teeth prepared usingthe preparation guide devices shown in FIGS. 93A and 98A, respectively.

FIG. 105 is a flowchart of the dental procedure in accordance with oneembodiment.

FIGS. 106-109 are screenshots of prospective prepared teeth.

FIGS. 110-115 are screenshots of preparation guide devices designedusing a CAD/CAM system in accordance with one embodiment.

FIG. 116 is a perspective view of a preparation guide device inaccordance with one embodiment as mounted on posterior teeth.

FIG. 117 is a perspective view of prepared posterior teeth and a splintprosthesis to be installed on the prepared posterior teeth.

FIG. 118 is a perspective view of the prepared posterior teeth and thesplint prosthesis shown in FIG. 117 as installed on the posterior teeth.

FIG. 119 is a perspective view of a preparation guide device inaccordance with another embodiment as mounted on posterior teeth.

FIG. 120 is a perspective view of prepared posterior teeth and a splintprosthesis to be installed on the prepared posterior teeth.

FIG. 121 is a perspective view of the prepared posterior teeth and thesplint prosthesis shown in FIG. 120 as installed on the posterior teeth.

FIG. 122 is a perspective view of prepared posterior teeth and a splintprosthesis in accordance with one embodiment.

FIG. 123 is a perspective view of the prepared posterior teeth and thesplint prosthesis shown in FIG. 122 as installed on the posterior teeth.

FIG. 124 is a plan view of a tool guide way in accordance with oneembodiment.

FIG. 125 is a flowchart of changing tools during a cutting process inaccordance with one embodiment.

FIG. 126 is a side view of a hand piece and a tool guide way inaccordance with one embodiment.

FIG. 127-172 are screen shots of a process of designing a preparationguide device in accordance with one embodiment.

DETAILED DESCRIPTION OF EMBODIMENTS

Various embodiments of the present invention will now be described inmore detail with reference to the accompanying drawings. In thedrawings, similar symbols typically identify similar components, unlesscontext dictates otherwise. The illustrative embodiments described inthe detailed description, drawings, and claims are not meant to belimiting. Other embodiments may be utilized, and other changes may bemade, without departing from the spirit or scope of the subject matterpresented here. It will be readily understood that the aspects of thepresent disclosure, as generally described herein, and illustrated inthe drawings, can be arranged, substituted, combined, and designed in awide variety of different configurations, all of which are explicitlycontemplated and make part of this disclosure.

Definitions

Here are definitions of some terms and expressions used in thisdisclosure. These terms and other terms appearing in other locations ofthe disclosure are used consistently throughout the disclosure includingthe claims unless expressly stated otherwise.

“Abutment” or “abutment tooth” refers to a tooth, to which a prosthesisor a portion thereof is fixed. For example, a tooth adjunct to a missing(lost) tooth is used as an abutment to fix a prosthesis that includes anartificial tooth filling the space of missing tooth.

“Adjacent tooth” refers to a tooth located immediately next to orneighboring a subject tooth. For example,

“Lingual surface” is a side surface of a tooth that faces the tongue.“Buccal surface” is a side surface that faces the cheek and generallyfaces away from lingual surface. “Labial surface” is a side surface ofan anterior tooth that faces the lips and generally faces away from thelingual surface of the anterior tooth. “Proximal surfaces” refer to thetwo side surfaces of a tooth that face adjacent teeth. “Mesial surface”is one of the proximal surfaces and generally faces the center of thedental arch. “Distal surface” is the other of the proximal surfaces andfaces away from the center of the dental arch.

The term “preparation” of a tooth refers to cutting, reducing,modifying, ablating, and/or grinding of the tooth to remove or delete aportion or portions of the tooth such that the prepared tooth is readyfor installing a dental prosthesis. “Before preparation” or “withoutpreparation” refers to a state in which the tooth subject to preparationhas not been prepared at all or sufficient to ready for installing thedental prosthesis. Thus, even if the tooth has been somewhat cut,reduced, modified ablated, and/or ground, it is still in the state of“before preparation” or “without preparation” if it is not yet readilyengageable with the particular prosthesis fabricated for installing withthe prepared tooth, with no additional cutting, reducing, modifying,ablating or grinding of the particular tooth. When the preparation ofthe tooth is complete or finished, i.e., “after completion,” theprepared tooth can be engaged with a particular portion of theprosthesis that is designed to be engaged with the prepared tooth,without additional cutting, reducing, ablating, or grinding of theprepared tooth.

The terms indicating directions or relative positions, such as up, down,top, bottom, side are used only to identify certain features more easilyor to make such features more easily understood. The terms themselves donot limit the present invention to particular directions or positions intheir literal meaning. For example, many embodiments disclosed in thisapplication are illustrated and described in terms of lower teeth, i.e.,teeth in the lower jaw. However, the embodiments or any claimedinventions are not limited to lower teeth. Also, for example, sometimesthe terms “top” may be used to indicate that it is away from the gum,gingival or root, as opposed to limit its absolute location. One ofordinary skill in the art will understand the relative nature of theseterms and will be able to appreciate their meaning in the context.

Dental Preparation for Restorations

In the conventional dental procedure for restorations, the patient'steeth are first prepared before making an appropriate restoration. Morespecifically, the dentist and/or dental practitioner prepare thepatient's teeth first, make an impression of the prepared teeth,fabricate a prosthesis based on the impression, and install theprosthesis on the patient's teeth. FIG. 1 illustrates preparing teeth.The dentist (not shown) grinds or cuts teeth 70 using hand piece 230 andassociated burr 200. The amount of deletion of the teeth or the level ofprecision largely depends on the hand skills and experience of thedentist. FIG. 2 depicts the prepared teeth 70 (the teeth afterpreparation) and a prosthesis 50 to be installed on the teeth 70. Theteeth 70 of FIG. 2 represents that they are modified excessively, andthat the cut is rough or not smooth. This result may not be uncommonwhen the dentist did not have good hand skills. Even dentists with verygood hand skills and experience, the preparation for dental restorationstypically cut into the dentin inside the enamel, which can lead to arisk of damaging pulp tissues or nerve cells.

Manufacturing Prosthesis Prior to Preparing a Tooth

In embodiments, a dental prosthesis is provided prior to toothpreparation, and the prosthesis can be installed immediately after thepreparation. In embodiments, the dental prosthesis can be installed overthe prepared tooth without modifying the provided prosthesis to fit itwith the prepared tooth. In embodiments, the prepared tooth will need tohave shapes and configurations that are substantially exactlycomplementary and counterpart of the shapes and configurations of to thepre-made prosthesis with high level of precision. If the preparation isnot well complementing or corresponding to the configurations of thepre-made prosthesis, it would be likely that the prosthesis would notfit the prepared tooth without further modification, cutting orgrinding.

Preparing a tooth to fit the pre-made prosthesis without furthermodification would be difficult to accomplish when relying only on thehand skills and experience of the dentist. In embodiments, a dentalpreparation guide device is introduced. In embodiments, this preparationguide device guides the movement of a cutting tool such as a burr (hencethe hand piece) along a predetermined path or trajectory so that thetooth can be cut as planned without much relying on hand skills of thedentist. In embodiment, the preparation guide device and the pre-madeprosthesis are related such that preparing a tooth using the preparationguide device will result in a prepared tooth that fits well the pre-madeprosthesis without further modifications of the prepared tooth orprosthesis.

Dental Procedure

In embodiments, new dental procedures can be developed using thetechnology of providing a dental prosthesis before preparing a tooth.Now an embodiment of dental procedure is discussed referring to FIG.105. When a dentist or dental practitioner examines teeth of patient andidentifies a need for dental restoration. The dentist develops a planfor dental restoration. S100. Upon the patient's approval of the plan,three-dimensional (3D) image data of the patient's oral featuresincluding a subject tooth is acquired. S200. The 3D image data is thenused to design a prospective post-preparation image, which is aprospective image of the subject tooth after a proposed preparation.S300. Optionally, a cutting tool is designed for the proposedpreparation. S400. Then, the extent of preparation is considered anddetermined for arriving at the prospective post-preparation image inactual tooth. S500. With the determined extent of preparation, now thestructures of a preparation guide device are designed. S600. Further,based on the prospective post-preparation image, a dental prosthesis isdesigned. S700. Using the designs made thus-far, the cutting tool,preparation guide device and prosthesis are manufactured. S620, S640 andS800. Subsequently, these manufactured devices are provided to thedentist. S900. The dentist prepares the subject tooth using thepreparation guide device and cutting tool. S1000. Immediately after thepreparation, the dentist installs the prosthesis onto the preparedtooth. S1100.

Impression before Preparing a Tooth

In embodiments, 3-dimensional (3D) image data of the patient's teeth ororal configurations and features is obtained before preparing a toothsubject to restoration. Then, the 3D image data is processed to producea dental prosthesis and a preparation guide for preparing the tooth tofit the particular prosthesis. In one embodiment, the 3D image data isconveniently obtained using a 3D scanner when it is available. Inanother embodiment when a 3D scanner is not available, the 3D image datais obtained by first taking a copy (impression) of patient's oralfeatures and the 3D image data is taken from the copy where a 3D scanneris available.

When the patient visits the dentist's office or a clinic, the dentist ordental practitioner examines the patient's teeth and proposes, forexample, a dental restoration or prosthesis for one tooth. Once thepatient approves the dental prosthesis, 3D image information/data of thesubject tooth and features of neighboring teeth is collected using a 3Dscanner or the impression technique. The dentist does not cut or preparethe subject tooth before obtaining the 3D image data. In embodiments,scanning the patient's oral features can be done at the dentist'soffice, a clinic, a dental lab, or some other place. Alternatively,taking an impression of the patient's oral features can be done at thedentist's office, a clinic, a dental lab, or some other place.Converting the impression to 3D image data can be done at anyappropriate location and by any appropriate persons.

Prospective Post-Preparation Shape

In embodiments, a CAD/CAM system is used to process the 3D image data toprovide a prospective post-preparation shape, which is acomputer-modeled prospective shape or image of the tooth after apreparation. The prospective post-preparation image illustrates aresulting shape of the tooth (with or without neighboring tooth orteeth) that would be obtained when an imaginary preparation has beenconducted on the tooth. In one embodiment, a prospectivepost-preparation shape or image is obtained based on the 3D image dataand using parameters for a proposed preparation. In embodiments,multiple prospective post-preparation shapes or images can be obtainedusing different parameters for preparation. In one embodiment, onedesired prospective post-preparation shape can be chosen. Alternatively,by selecting certain appropriate parameters for preparation, aprospective post-preparation shape may be automatically generated. Inembodiments, the prospective post-preparation shape is provided in a 3Dimage data and can be displayed on a display screen.

Axis of Insertion

According to embodiments, when designing preparation guide device, aCAD/CAM system is used to process the 3D image data (of the patient'soral features) to determine a path of insertion (or approach) ofprosthesis toward the prepared tooth for installing. In one embodiment,in designing a prospective post-preparation shape, the 3D image data isprocessed to determine a preferred or optimum path of insertion of theprosthesis for installing. In one embodiment, the preferred or optimumpath of insertion has an axis of insertion or approach, in whichdirection the prosthesis is suggested to move for most convenientengagement between the prosthesis and the prepared tooth.

In one embodiment, the path and axis of insertion is chosen ordetermined such that when viewing the prospective post-preparation shapealong the axis of insertion, no substantial undercuts can be found onthe cut or modified side surfaces of the prospective post-preparationshape. In one embodiment, the path and axis of insertion is chosen ordetermined such that cutting or modifying of the tooth can be minimizedto make that when viewing the prospective post-preparation shape alongthe axis of insertion, there are no substantial undercuts on the cut ormodified side surfaces of the prospective post-preparation shape. In oneembodiment, the path and axis of insertion is chosen or determined suchthat cutting or modifying of the tooth can be balanced (no heavy cuttingon one surface) between two or more surfaces that are to be cut formaking that when viewing the prospective post-preparation shape alongthe axis of insertion, there are no substantial undercuts on the cut ormodified side surfaces of the prospective post-preparation shape.

High Level of Precision

In embodiments, there are no substantial undercuts on the side surfacesof the prospective post-preparation shape when viewing in the directionof the determined axis (path) of insertion. This can be accomplished byutilizing a preparation guide device that is designed in view of thedetermined axis of insertion. When relying on hand skills of a dentist,it would be difficult to prepare a tooth without significant undercutson the side surfaces of a tooth. In order to avoid significantundercuts, cutting of a side surface should result in a significantslope angle of the side surface against the axis of insertion like over6°.

In one embodiment, the preparation guide device allows a level ofprecision that would not be possible when relying on the dentist'sskills only. Accordingly, side surfaces of a tooth can be preparedwithout significant undercuts even if the side surface is modified tohave only a minimum slope (the slope against the axis of insertion). Inone embodiment, the small slope is possible because the preparationguide device includes a tool guide channel that includes configurationsfor keeping the axis of rotation of the burr against the axis ofinsertion constant. The orientation can be maintained even while thetool is moving during cutting. For example, the axis of rotation of theburr and the axis of insertion can be parallel while cutting. By cuttingas explained above, precise cut surface can be obtained.

In one embodiment, the slope angle of the side surface against the axisof insertion is about 0° to about 3°, although not limited thereto. Inone embodiment, a sloping surface can have an angle greater than this,e.g., about 3° to about 6° and also about 6° to about 15°.

Design of Preparation Guide Device

In embodiments, a CAD/CAM system is used to process the 3D image datafor designing a preparation guide device. In one embodiment, thepreparation guide device is designed based on the 3D image data of thepatient's oral features prior to preparation and the 3D image data ofthe prospective post-preparation shape or image. In embodiments, thepreparation guide device is designed to fit the subject tooth (or teeth)for preparation and/or its neighboring teeth. In embodiments, thepreparation guide device is designed to include features to assist,facilitate and/or guide cutting, modifying, grinding, ablating of asubject tooth (or teeth) for fitting a desired prosthesis.

Design of Preparation Guide Device—Fitting with Tooth

In embodiments, the preparation guide device is designed to have two ormore sidewalls and a top wall interconnecting the two or more sidewalls.In embodiments, the preparation guide device includes an interior spaceor a recess defined by the top wall and two or more sidewalls. Inembodiments, the interior space or recess is configured to receive oneor more teeth. In one embodiment, the interior space or recess isconfigured to tightly fit one or more teeth. In one embodiment, innersurfaces of interior space or recess are configured to engage withportions of one or more teeth. In one embodiment, the inner surfaces ofthe interior space or recess include features that are at least partlycomplementary to the exterior configurations of the one or more teeth sothat the tooth is well fit in the recess.

In one embodiment, the top wall is to cover, correspond to and/or facethe occlusal surface of a posterior tooth. In one embodiment, the topwall is to cover, correspond to and/or face the occlusal surfaces of twoor more teeth. In one embodiment, the top wall is to cover, correspondto and/or face the incisal edge of an anterior tooth. In one embodiment,the top wall is to cover, correspond to and/or face the occlusal surfaceof one posterior tooth and the incisal edge of an anterior tooth.

In one embodiment, the preparation guide device includes two sidewalls:one sidewall covers, corresponds to and/or faces the lingual surface ofa tooth, and the other sidewall covers, corresponds to and/or the buccalsurface of the tooth. In one embodiment, one sidewall covers,corresponds to and/or faces the lingual surfaces of two or more teeth.In one embodiment, one sidewall covers, corresponds to and/or faces thebuccal surfaces of two or more teeth. In one embodiment, the preparationguide device includes another sidewall that covers, corresponds toand/or a mesial surface of the tooth.

Design of Preparation Guide Device—Tool Guide Channel

In embodiments, the preparation guide device is designed to include atool guide way or tool guide channel, which is to guide a cutting toolto stay in its trajectory. In one embodiment, the tool guide way is athree-dimensional structure formed in the body of the preparation guidedevice that is to engage with a cutting tool or burr and to permitmovement of the cutting tool along its trajectory.

In one embodiment, the preparation guide device includes an engagementfeature configured to engage with an engagement feature of the cuttingtool or burr. In one embodiment, the engagement feature of thepreparation guide device is generally structurally complementary to theengagement feature of the burr. In one embodiment, the engagementfeature of the preparation guide device is sized to accommodate theengagement feature of the burr while being shaped and sized to preventdisengagement of the burr except moving in directions along thetrajectory. In one embodiment, the engagement feature of the preparationguide device includes a groove extending along the trajectory. In oneembodiment, the size and shape of the groove is substantially maintainedthroughout the trajectory or at least part of the trajectory.

In one embodiment, the engagement feature of the burr may not bedisengaged until the burr reaches a disengaging feature formed in thetrajectory of the tool guide channel. In one embodiment, the disengagingfeature of the tool guide channel includes lacking of the particularengagement feature that maintains the engagement feature of the burr. Inone embodiment, one or more disengagement features are located in themiddle of the trajectory. In one embodiment, at least one disengagementfeature is located at an end of the trajectory.

In one embodiment, the engagement feature of the preparation guidedevice extends in the body of the preparation guide device, whichdefines the trajectory of the tool guide channel. In embodiments, theextension of the engagement feature (and the trajectory) may be straightand/or curved. In embodiments, the extension of the engagement feature(i.e., the trajectory) may be made in any directions in thethree-dimensional space or body the preparation guide device.

In embodiments, once engaged with the tool guide channel, the burr'sdistal (tip) portion is buried in the body of the preparation guidedevice or enters the interior space or recess defined by the walls ofthe preparation guide device, while the burr's proximal portion iscoupled to a hand piece gripped by the dentist. Once the burr's tipportion has entered the interior space, the burr's cutting head maycontact a tooth surface and cut it as the burr rotates. As the burrmoves along the trajectory of the tool guide way, the burr's cuttinghead cuts the tooth only along the trajectory as designed or planned.

Design of Preparation Guide Device—Anti-Tilting Features

In one embodiment, the preparation guide device is designed to includeanti-tilting structures and/or configurations of the tool guide way thatprevents or reduces the possible tilting of the burr in certaindirections while the burr is engaged in the tool guide way. In oneembodiment, the anti-tilting feature is configured to prevent or reducetilting in a direction of burr's movement at a point in the trajectoryof the tool guide channel. In one embodiment, the anti-tilting featureis configured to prevent or reduce tilting in a plane perpendicular tothe direction of burr's movement at a point in the trajectory of thetool guide channel. In one embodiment, the anti-tilting structures areincorporated or integrated in the engagement feature of the tool guidechannel.

In one embodiment, the anti-tilting structures include two or moreengagement features arranged in the body of the preparation guidedevice, in which each of the two or more engagement features canindividually function as an engagement feature with the counterpartfeature of the burr without the other(s). In one embodiment, theanti-tilting feature of the preparation guide device includes two ormore grooves that are extending substantially parallel to each other. Inone embodiment, the two or more grooves are about the same shape andsize. In another embodiment, the two or more grooves are ofsubstantially different shapes and sizes. In embodiments where thepreparation guide device includes an ant-tilting feature, the cuttingtool (burr) also includes a complementary or counterpart feature thatcooperates with the anti-tilting feature of the preparation guidedevice.

Design of Prosthesis

In embodiments, a CAD/CAM system is used to process the 3D image datafor designing a desired prosthesis to install onto a tooth (or teeth)prepared using the preparation guide device. In one embodiment, theprosthesis is designed to have features to engage with and fixed to theprepared tooth. In one embodiment, the prosthesis is designed to includeone or more surfaces for cementing to the prepared tooth. In oneembodiment, the prosthesis is designed to include two surfaces that areopposing such that the two surfaces interpose the prepared tooththerebetween. In one embodiment, the prosthesis is designed to includeat least one anchoring feature such as inlays. In one embodiment, theprosthesis is designed to include one or more bridging portions, each ofwhich is configured to fix to the prepared tooth. In one embodiment, theprosthesis is designed to include a closed loop portion configured toencircle or surround the prepared tooth, in which the closed loopportion does not include a top covering and therefore is not a crown. Inone embodiment, the prosthesis is designed based on the 3D image data ofthe prospective post-preparation shape or image. In one embodiment, theprosthesis is designed based on a desired appearance of the tooth andthe 3D image data of the prospective post-preparation shape or image. Inembodiments, the prosthesis is in the form of a crown, a crown andbridge, crownlay, laminate, veneer, inlay, onlay, splinting prosthesis,etc. although not limited thereto.

Designing Burrs

In one embodiment, a cutting tool such as a burr is designed along withthe preparation guide device. In one embodiment, design parameters for aburr includes the length of the burr, the length of cutting portion(cutting head) of the burr, the length of abrasive portion of the burr,the radius or diameter of the burr, the tapering angle of the burr, theheight of the cutting portion from the tip of the burr, etc. In oneembodiment, one or more parameters for the burr are used in designing ofthe preparation guide device. In one embodiment, the burr is designed toinclude engagement structures that enable specific engagement withengagement structures of the tool guide way or tool guide channel. Inone embodiment, the burr is designed to include engagement structuresthat are complementary to the engagement structures of the tool guideway or tool guide channel with a slight gap therebetween, which permitsmovement of the burr along the trajectory or path of the tool guide way.In one embodiment, the burr is designed to include one or more featuresthat reduce tilting of the burr in the tool guide channel whiletraveling along the tool guide channel. In one embodiment, two or moreburrs are designed for use with one preparation guide device.

In the alternative, the cutting tool can be selected from pre-madeburrs. In such embodiments, the pre-made burrs include features that areconfigured to engage with engagement features of preparation guidedevices. In such embodiments, parameters of the pre-made burrs arealready considered in the development of the preparation guide device.In one embodiment, a particularly shaped burr is already preselected foruse with dental preparation guides.

Time and Location for Designing and Manufacturing

In one embodiment, designing the preparation guide device can occurprior to, subsequently to, or simultaneously as designing theprospective post-preparation shape or image. In one embodiment,designing the prosthesis can occur prior to, subsequently to, orsimultaneously as designing the prospective post-preparation shape orimage. In one embodiment, designing the preparation guide can occurprior to, subsequently to, or simultaneously as designing theprosthesis. In one embodiment, this series of processes occurs at thedentist's office, a dental lab, or some other location. These processescan occur during the patient's initial visit for diagnosis orafterwards.

When designing is completed, the devices are manufactured based on theirdesign. In one embodiment, the preparation guide device is manufacturedusing various technologies including 3D printing. In embodiments, thepreparation guide device is manufactured at the dentist's office, dentallab or another location. In embodiments, the prosthesis device ismanufactured at the dentist's office, dental lab or another location.

Minimally Invasive Preparation Technique

In embodiments, the prospective post-preparation shape or image isobtained using parameters for a minimally invasive preparation, althoughnot limited thereto. In one embodiment, the minimally invasivepreparation involves cutting of the tooth only within its enamel layer.In one embodiment, the minimally invasive preparation involves cuttingof the tooth substantially within its enamel layer, in which cuttinginto the dentin tissues is permitted as long as cutting into the dentintissues is maintained as less than about 30%, about 25%, about 20%,about 15% about 10%, about 5% of the total cut surface areas of thetooth. In one embodiment, the preparation guide device is designed toenable the minimally invasive dental preparation. Accordingly, theprosthesis is designed to fit the minimally prepared tooth.

Tooth Preparation

Once the prosthesis and preparation guide device are custom-made, theyare provided to the dentist. In one embodiment, the prosthesis andpreparation guide device are provided to the dentist as a kit. In oneembodiment, the kit of prosthesis and preparation guide device furtherincludes one or more appropriate burrs for use with the preparationguide device. Subsequent to the receipt of preparation guide device, thedentist conducts dental preparation of the subject tooth using thepreparation guide device. In embodiments, the dentist connect anappropriate burr to a hand piece, engages the burr with the tool guidechannel of the preparation guide device, and then moves the burr alongthe trajectory or path of the tool guide channel while running the burr.

As the burr moves along the path of the tool guide channel, the burrcuts the subject tooth as prescribed in accordance with the tool guidechannel. In embodiments, the preparation guide device prevents freemovement of the burr and permits the movement of the burr only along thetrajectory of the tool guide channel. In embodiments, the preparationguide device substantially prevents tilting of the burr while engagedwith the tool guide channel. As such, in embodiments, the subject toothis prepared as planned and as prescribed in the preparation guidedevice, in terms of the locations and areas of cutting, the depth ofcutting, the accuracy and precision of cutting, etc. In embodiments,once prepared the subject tooth does not include undercuts on theprepared surfaces.

Installing Prosthesis

In embodiments, once the tooth preparation is finished, the prosthesisis installed onto or over the prepared tooth. In embodiments, theprosthesis is engaged with the prepared tooth and cemented to be fixedto the prepared tooth. In one embodiment, the prosthesis is cemented orinstalled to the prepared tooth without modifying the prosthesis aftercompletion of preparation using the preparation guide device or afterremoving the preparation guide device from the patient's mouth. In oneembodiment, the prosthesis is cemented or installed to the preparedtooth without modifying the prepared tooth after completion ofpreparation using the preparation guide device or after removing thepreparation guide device from the patient's mouth. In one embodiment,the prosthesis is cemented or installed to the prepared tooth withoutmodifying the prosthesis and further without modifying the preparedtooth after completion of preparation using the preparation guide deviceor after removing the preparation guide device from the patient's mouth.

Time Frame

In one embodiment, the following steps occur on the same day: selectinga dental treatment using a prosthesis; obtaining 3D image data of thesubject tooth; designing the prosthesis; designing the preparation guidedevice; installing the preparation guide device within the patient'smouth; preparing the subject tooth using the preparation guide device;and installing the prosthesis to the prepared tooth. In one embodiment,all of the foregoing steps are completed during the patient's visit tothe dentist's office or clinic without leaving the location.

In one embodiment, selecting a dental treatment occurs during thepatient's initial visit to the dentist's office or clinic; and preparingthe subject tooth using the preparation guide device, and installing theprosthesis to the prepared tooth occur during the next visit. The stepsof obtaining 3D image data of the subject tooth, designing theprosthesis, and designing the preparation guide device occur on the sameday as the day of selecting the dental treatment or on any subsequentday.

Prospective Post-Installation Image

In one embodiment, the CAD/CAM system processes the 3D image data of thepatient's tooth to generate a prospective post-installation shape orimage, which is a computer-modeled shape or image of the tooth afterinstallation of a proposed prosthesis. The prospective post-installationimage illustrates a resulting shape of the tooth (with or withoutneighboring tooth or teeth) that would be obtained once an imaginary(proposed) prosthesis has been installed. In one embodiment, theprospective post-installation image includes the proposed prosthesis andone or more adjacent teeth. In one embodiment, various prospectivepost-installation shape or image are provided for the same prosthesis.In one embodiment, various prospective post-installation shapes orimages are provided with more than one prostheses having differentappearance. In one embodiment, one or more prospective post-installationshapes are provided in the form of still images and/or videos(collectively “images.”)

Accommodating Patient's Input on the Design

In one embodiment, one or more images representing/illustrating theprospective shape(s) are provided to the patient and/or guardian(collectively “patient”) for review. In one embodiment, the patient isprovided the opportunity to submit comments about the images or toapprove the proposed prosthesis. In one embodiment, the preparationguide device is designed after receiving or in response to the patient'sacceptance or approval of the proposed prosthesis. In one embodiment,the preparation guide device is fabricated after receiving or inresponse to the patient's acceptance or approval of the proposedprosthesis. In one embodiment, if the patient does not approve theproposed prosthesis, designing and manufacturing a preparation guidedevice is delayed.

In one embodiment, the patient provides a comment or request forchanges, the proposed prosthesis is modified in view of the comment orrequest, and one or more images representing/illustrating prospectiveshape(s) of the tooth after installation of the modified proposedprosthesis are provided to the patient. In one embodiment, the patientis provided with two or more images representing or illustrating theprospective shapes that are of two or more proposed prostheses, and inresponse the patient is provided with the opportunity to select orchoose one of the two or more proposed prostheses with or without theopportunity to provide a comment or request to modify. In oneembodiment, the preparation guide device is designed after receiving orin response to the patient's selection of one of the proposedprostheses. In one embodiment, the preparation guide device isfabricated after receiving or in response to the patient's selection ofone of the proposed prostheses. In one embodiment, if the patient doesnot make a selection, designing and manufacturing a preparation guidedevice is delayed.

In embodiments, the images of the prospective shape(s) are provided tothe patient in various ways. In embodiments, the patient's input (acomment, request, approval and/or selection) can be provided in variousways. In one embodiment, the patient's input can be made and receivedduring consultation with the dentist, dental practitioner or person incharge either at the dentist's office or another place or during atelephonic, video or web conference. In one embodiment, the patent'sinput can be made and received in its entirety, in part, or individuallyby email as contents of an email or attachment, by mail, or on a websitethat allows the patient to take the above steps.

Preparation Guide Device—Surfaces/Portions to Cut

In the configurations of a tooth, there are no sharp boundaries betweenadjacent surfaces of a single tooth. Many times, people can easily agreethat a point on a tooth belongs to one of the five surfaces of thetooth, i.e., the lingual surface, mesial surface, buccal surface, distalsurface and occlusal surface (incisal edge). Many other times, however,people may not easily that a point on a tooth belongs to one of the fivesurfaces of the tooth. Thus, in this disclosure and application, cuttingor modifying a first surface (one of the five, e.g., lingual surface) ofa tooth means cutting or modifying at least a portion that is clearlybelonging to the first surface (here, e.g., the lingual surface) with noor little disagreement. On the other hand, when cutting or modifying aportion that is not clearly belonging to one surface and therefore therecould be some disagreement about which surface it belongs to between two(or three) surfaces, it is considered and determined as cutting ormodifying of one of the two (or three) surfaces, if that portion isisolated like an island in the uncut area and if that portion is notintegrated as a single large cut area with another cut portion that isclearly belonging to one of the five surfaces with no or littledisagreement. When a boundary area between two adjacent surfaces iswide, and therefore a cut portion within the boundary area looksextending into the two adjacent surfaces, it is considered anddetermined that the two surfaces are cut as opposed to one. One ofordinary skill in the art such as a dentist should be able to appreciatethe criteria for consideration and determination provided herein anddetermine which surface(s) a cut portion belongs to.

In embodiments, a preparation guide device is used to cut or modifiedone or more surfaces of a tooth, i.e., the lingual surface, mesialsurface, buccal surface, distal surface and occlusal surface (incisaledge). Here, cutting or modifying a surface means that the whole surfaceor at least a portion of the surface is cut or modified. In oneembodiment, a preparation guide device is used to cut only one surfaceof a tooth. In other embodiments, a preparation guide device is used tocut only two surfaces of a tooth, in which the two surfaces are opposingor neighboring, and in which the cut portions of the two surfaces areconnected together or disconnected by an intervening uncut portiontherebetween. In other embodiments, a preparation guide device is usedto cut only three surfaces of a tooth. In other embodiments, apreparation guide device is used to cut only four surfaces of a tooth.In other embodiments, a preparation guide device is used to cut fivesurfaces of a tooth.

Preparation Guide Device—Two or More Separate Tool Guide Ways

In one embodiment, a single preparation guide device includes two ormore separate tool guide ways that are separate from each other in a waythat there is a blockage between the two or more tool guide ways where aburr cannot pass through. In this embodiment, once the burr is engagedwith one of the tool guide ways, the burr must be first removed from thetool guide way in order for the particular burr to be inserted in theother tool guide way(s).

In one embodiment, the preparation guide device includes one tool guideway configured for preparing one tooth and another tool guide wayconfigured for preparing another tooth. Referring to FIGS. 66-74, forexample, the preparation guide device has one tool guide way for thefirst molar and another tool guide way for the first and secondpremolars. In one embodiment, the preparation guide device includes twoor more tool guide ways configured for preparing a single abutmenttooth.

Preparation Guide Device—Preparing Three or Four Side Surfaces of aSingle Tooth

In embodiments, the preparation guide device is configured to cut ormodify three or four side surfaces of a single tooth, i.e., lingual,mesial, buccal, and distal surfaces of the tooth. In one embodiment, noadditional preparation guide devices are used to cut or modify the threeor four surfaces. Here, cutting or modifying a side surface refers tocutting or modifying at least a portion of the whole area of the sidesurface. In one embodiment, the preparation guide device includes asingle tool guide channel or way that is configured to cut or modifythree or four side surfaces of a single tooth, i.e., lingual, mesial,buccal, and distal surfaces. In one embodiment, the preparation guidedevice is configured to cut or modify four side surfaces to form aclosed loop of cut areas when viewing in a direction toward the occlusalsurface or incisal edge of the tooth. In one embodiment, the preparationguide device includes a tool guide channel forming a closed loop, ringshape or annular configuration when viewing in a direction toward theocclusal surface or incisal edge of the tooth.

In one embodiment, the preparation guide device is configured to cut ormodify four side surfaces of a single tooth without forming a closedloop of cut surfaces when viewing in a direction toward the occlusalsurface or incisal edge of the tooth. In this embodiment, at least parpart of one side surface is not cut or modified when viewing in adirection toward the occlusal surface or incisal edge of the tooth. Theportion that is not modified or cut includes a contact point of thattooth wit with an adjacent tooth. In one embodiment, the preparationguide device includes a single tool guide channel that is configured tocut or modify all four side surfaces of a single tooth, in which thesingle tool guide channel does not have a closed loop trajectory whenviewing in a direction toward the occlusal surface or incisal edge ofthe tooth. In this embodiment, once a burr is engaged with the singletool guide channel, traveling through the tool guide channel mayaccomplish cutting or modifying of the four surfaces without having toremove the burr from the tool guide channel, although not limitedthereto.

Preparation Guide Device—Preparing for a Crown

In one embodiment, one or more preparation guide devices are used toprepare a tooth for a crown prosthesis, in which the lingual, mesial,buccal, distal, and occlusal surfaces of the tooth are cut. In oneembodiment, a single preparation guide device includes one or more toolguide ways that are configured to cut all of these surfaces without theneed of additional preparation guide device and further without cuttingany surfaces of the tooth in the absence of a preparation guide device.In one embodiment, a single preparation guide device includes one toolguide way formed in the occlusal surface that form a closed loop that isused to cut all four side surfaces. This single preparation guide deviceincludes one or more tool guide way formed the buccal sidewall and/orlingual sidewall that is/are configured to cut the occlusal surface ofthe tooth.

In one embodiment, two preparation guide devices are used to prepare atooth for a crown prosthesis without the need of additional preparationguide device and further without cutting any surfaces of the tooth inthe absence of a preparation guide device. In this embodiment, onepreparation guide device includes one tool guide way formed in theocclusal wall for cutting the buccal or lingual surface of the tooth andthe other tool guide way formed in the buccal or lingual sidewall forcutting at least part of the occlusal surface of the tooth. Further, theother preparation guide device includes one tool guide way formed in theocclusal wall for cutting the lingual or buccal surface of the tooth andthe other tool guide way formed in the lingual or buccal sidewall forcutting the remainder of the occlusal surface of the tooth. In anotherembodiment, more than two preparation guide devices are used to preparea tooth for a crown prosthesis.

Restoring Missing Teeth

Referring to embodiments of FIGS. 53, 63, 65, 71, 72, and 78, a bridgeprosthesis 50 that includes an artificial tooth 52 is used to restore amissing tooth. In an embodiment, a bridge prosthesis 50 includes fixingportions 54 and an artificial tooth 52 to be placed in the location of amissing tooth. The fixing portions 54 are cemented with abutment teeth70. Abutment teeth 70 are prepared to tightly fit the fixing portions54. In an embodiment for a crown and bridge prosthesis 50, fixingportions 54 are of a crown shape. Such fixing portions 54 bond withabutment teeth 70, thereby fixing the prosthesis 50.

In embodiments, artificial tooth 52 can be made of various materials,including ceramic, metallic, and polymer materials. Examples of metallicmaterials that can be used include gold, platinum, gold alloys, platinumalloys, titanium, titanium alloys, tantalum, and tantalum alloys.Examples of ceramic materials that can be used include zirconia,alumina, hydroxyapatite, tricalcium phosphate ceramic, glass, andcrystallized glass. In fact, any material used for dental purposes canbe employed as long as it is not harmful to the human body, isbiocompatible, can be formed into artificial teeth, and can endurephysical force exerted on teeth.

Elastic deformation of a fixing portion 54 may or may not be requireddepending on the circumstances, and so it is important to select anappropriate material for each case. Metallic materials are generallyflexible, and ceramic materials generally are not. In variousembodiments of the invention, prosthesis 50 can be installed by movingit linearly according to a predetermined axis of insertion from abovethe occlusal surface of the teeth towards the gum 68. In suchembodiments, because neither the cut portion of tooth nor the fixingportion 54 of the prosthesis 50 has any undercut, no elastic deformationof the fixing portion 54 is required while the prosthesis 50 isinstalled. Therefore, according to such embodiments, materials withalmost no flexibility can be used in nearly all cases.

Preparation Guide Device

Referring to FIGS. 66-74, a preparation guide device 100 is used to cuta second molar and first and second premolars as abutments such that aprosthesis 50 can be installed in cases where a first molar is missing.The preparation guide device 100 includes a tool guide way or channel120 for cutting a second molar's side surface, except for a portion ofthe distal surface. In addition, the preparation guide device 100 has asingle tool guide way 120 for cutting a first premolar's lingualsurface, a second premolar's lingual surface, and a portion of a firstmolar's proximal surface. The single tool guide way 120 for premolarsallows for cutting of two premolars at once. As shown in FIG. 71, theprosthesis 50 exposes the premolar's buccal surface as is without anycutting thereof such that the prosthesis is not easily visible. Theprosthesis 50, nonetheless, obtains sufficient retention force by beinginstalled on two premolars. Although one preparation guide device 100 isconfigured to cut three teeth in the embodiment, other embodiments canhave a separate guide device for cutting each tooth.

In an embodiment, the preparation guide device 100 is engaged such thatit does not move within a patient's mouth, and guides the cutting of anabutment's 70 side surfaces. In an embodiment, a preparation guidedevice 100 is placed over the location of a missing tooth and abutments70 on each side thereof. In other embodiments, a preparation guidedevice covers not only abutment teeth 70, but also teeth adjacent to theabutments 72 and/or the gum or even alveolar bone.

Mounting of Preparation Guide Device

In an embodiment, a preparation guide device 100 has a sidewall 110 thatextends along the side surface of teeth. The sidewall has a lingualsidewall 111 that extends along the lingual surface and a buccalsidewall 112 that extends along the buccal surface. The interior ofthese sidewalls 110 correspond to the shapes of the lingual and buccalsurfaces of teeth. However, in certain embodiments, the interior surfaceof the sidewall beneath the survey line 84 is configured to not have anyundercut (see FIGS. 6 and 9) to prevent problems that can arise whileinstalling the preparation guide device 100 inside a mouth. Inembodiments shown in FIGS. 6 and 9, the top part 1104 of the interiorsidewalls 110 comes into contact with a tooth's side surfaces.Accordingly, the interior shape of that top part is formed as the shapeof the tooth. In contrast, the bottom part 1106 does not come intocontact with the tooth's side surfaces. In embodiments where thepreparation guide device is made of a flexible material, however,undercut can be present on surfaces beneath the survey line 84 (see FIG.55B). Such guide devices can well retain their original state ofinstallation.

In an embodiment, a preparation guide device 100 has a top wall 114 thatcovers teeth by connecting a lingual sidewall 111 and a buccal sidewall112. The interior of the top wall 114 is configured to be of a shapethat corresponds to the occlusal surface of a tooth to be accommodated.As shown in FIG. 66, in an embodiment where a second molar is to beaccommodated, a preparation guide device 100 has a proximal sidewall 113that connects the lingual sidewall 110 and the buccal sidewall 112.

Burr

Referring to FIGS. 7-10, 12, 13, 24-43, and 88, a burr 200 has a shank202, a neck 203, and a cutting head 204. The shank 202 is the portionthat is fixed to the hand piece 230. The cutting head 204 is the portionthat contacts teeth for cutting. The neck 203 connects the cutting head204 and the shank 202 and is the portion that is guided by a guide slotof a preparation guide device 100, as discussed below.

In an embodiment, a burr 200 is made of tungsten carbide or stainlesssteel, and abrasives are attached at the cutting head 204. For example,a diamond abrasive can be used. In another embodiment of the invention,the cutting head can include multiple cutting edges instead ofabrasives.

In an embodiment, the neck 203 fits within and moves along the toolguide way 120, which comprises the shape of a guide slot as discussedbelow. For such purposes, referring to FIGS. 38, 39, and 88, in anembodiment, the neck 203 has two sphere-shaped guide projections 208,210. As the burr 200 rotates and moves along the tool guide way 120, theguide projections 208, 210 move along grooves formed on the wall of thetool guide way 120 as discussed below. In some embodiments, the guideprojections 208, 210 can be disc-shaped. In other embodiments, the guideprojections 208, 210 can be in the shape of an oval, a cone, or atrapezoid. In some embodiments, the guide projections 208, 210 areconfigured as parts of the neck 203, but in other embodiments, the guideprojections can be separate from the neck. For example, a rotatable ringcan be separately installed on the neck 203 as a guide projection.

Hand Piece

In an embodiment, a hand piece 230 is a device that installs and rotatesa burr 200 (see FIGS. 7-10, 12, and 13). Generally, dental practitionershold a burr with their hands. The hand piece 230 has a chuck to whichthe shank 202 of a burr 200 is connected. The hand piece 230 has a motorthat can rotate the burr 200 at high speeds. In some embodiments, a handpiece 230 can be configured for high speed rotations (about 300,000 RPMto about 400,000 RPM) or for low speed rotations (about 3,000 RPM toabout 30,000 RPM).

Tool Guide Way or Channel

In an embodiment, a tool guide way 120 is provided to guide a burr 200such that it follows a predetermined path or trajectory. After the burr200 is properly inserted into the tool guide way 120 through an entrancehole, the burr 200 can only move along the predetermined path. The burr200 moves along the tool guide way 120 and removes or cuts teeth. In anembodiment, as shown in FIG. 66, a tool guide way includes a non-cuttingaccess way 1202. The non-cutting access way 1202 is a portion of thetool guide way 120 to guide a burr 200 to a location at which cutting isto begin. In some embodiments, the burr 200 does not cut teeth while itis traveling along the non-cutting access way. In embodiments in which atool hole is located near the point within the tool guide way at whichcutting is to start, a separate non-cutting access way may not benecessary.

Cutting Tooth along a Tool Guide Way

In an embodiment, a burr 200 may not cut teeth at every location along atool guide way 120. Whether or not a burr 200 cuts teeth at a givenlocation is determined by the radius of the burr 200 (size of a crosssection) and the distance between the tool guide way 120 and surface ofteeth. Because the radius of a burr 200 can change depending on theburr's lengthwise shape, the shape of the burr also affects the cuttingof teeth.

In an embodiment, the distance between a tool guide way 120 and surfaceof teeth can be defined as a distance d between the vertical centerlineof the tool guide way 120 and the surface of teeth, as shown in FIG. 6.In an embodiment, ideally, the vertical centerline of the tool guide way120 coincides with the axis of rotation 201 of the burr 200, asillustrated in FIG. 9. In some embodiments, the distance d between theaxis of rotation 121, 201 of the burr 200 and the surface of teeth canchange depending on the path of the tool guide way 120. Assuming a burr200 with a predetermined radius and shape is used, the depth of cuttingcan vary according to changes in the distance d changes, and there canbe sections where teeth are not cut at all. For example, although notshown in FIG. 6, in an embodiment, teeth are not cut along locationswhere the burr's 200 axis of rotation 121, 201 is farther out away fromteeth than the radius of the burr 200.

In one embodiment, a preparation guide device 100 is designed so that aburr 200 cuts teeth along all points on a path of a tool guide way 120.In an embodiment, the depth of cutting can be configured to be almostconstant at all points along a path or to vary greatly. In anotherembodiment, a preparation guide device 100 is designed so that a burr200 cuts teeth while moving along certain sections of the tool guide way120, but not along other sections. In an embodiment, a preparation guidedevice 100 is designed so that a section where the burr 200 moveswithout cutting teeth is followed by a connected section where the burrmoves while cutting teeth. In some embodiments, a preparation guidedevice 100 is designed so that a section where a burr 200 moves whilecutting teeth is located between, or intervenes, sections where the burrmoves without cutting teeth. In some other embodiments, a preparationguide device 100 is designed so that a section where the burr 200 moveswithout cutting teeth is located between, or intervenes, sections wherethe burr moves while cutting teeth. The various types of embodimentsdiscussed in this paragraph all assume using a burr with a predeterminedradius and shape.

No Cutting of Occlusal Surface

Referring to FIGS. 66-74, in an embodiment, a preparation guide device100 has two tool guide ways 120 for cutting side surfaces of teeth and anon-cutting access way. A first one of the two tool guide ways 120 isfor cutting a first molar, and the other is for cutting first and secondpremolars. Bridge prostheses 50 used in the illustrated embodiments donot require cutting occlusal surfaces. Since occlusal surfaces are notcut, a tool guide way for cutting occlusal surface is not necessary.

Restriction of Burr within Tool Guide Way

Referring to FIGS. 39A, 39B, 69A, and 69B, which show cross sections oftool guide ways 120, in an embodiment, a tool guide way 120 has twoguide side surfaces 128 that face each other. The two guide sidesurfaces 128 form a guide slot. When a burr 200 enters the guide slot,movement of the burr 200 is constrained and the burr 200 is guided alongthe tool guide way 120. The distance between the guide side surfaces128, that is, the width of the guide slot, is limited to reduce tiltingwhen a neck 203 of a burr 200 is inserted, but is large enough for theneck 203 to overcome friction and rotate. In an embodiment of theinvention, the tool guide way 120 is shaped as a guide slot, but thepresent invention is not limited to such embodiments.

In some embodiments, a portion of a burr 200 enters a guide slot andbecomes constrained in its movement, but other embodiments havestructures wherein a hand piece 230 is inserted into and constrained bya guide slot of a tool guide way 120. For example, in an embodiment asshown in FIG. 126, a structure 2301 of a hand piece 230 is inserted intoand constrained by a guide slot. In contrast, a burr 200 is not directlyconstrained by the guide slot. Alternatively, although not shown, otherembodiments can include configurations where both a structure of a handpiece 230 and a portion of a burr 200 are inserted into and constrainedby a tool guide way.

Using Two or More Burrs in One Tool Guide Way

While in some embodiments, a single burr is used for cutting tooth, inother embodiments two or more burrs can be used in cutting tooth. Forexample, in embodiments with thick portions to cut, a first burr can cutsome layers of the portion to be cut by moving along a tool guide way120, and a second burr can subsequently move along the same tool guideway 120 to cut the remaining layers in order to obtain a final cutshape. In another embodiment of the invention, a first burr can performa rough cut, and a second burr can subsequently perform a precise cut.

In one embodiment using two or more burrs, the two or more burrs enter atool guide way 120 through the same entrance. In another embodiment,referring to FIG. 124, burrs can be substituted in the middle of a toolguide way 120. To allow for such substitutions, an embodiment has amiddle tool hole 124a, or intermediate tool hole, formed in the middleof the tool guide way 120. Although not illustrated, some embodimentscan have two or more middle tool holes in a tool guide way 120 so thatit is possible to replace a burr two or more times. In an embodiment,first, a preselected first burr enters a tool guide way and cuts along afirst part 120a. Then, the first burr is removed through a middle toolhole 124a located on a terminal end of the first part 120a. Next, apreselected second burr enters the tool guide way through the middletool hole 124a and cuts teeth following the second part 120b of the toolguide way 120. Here, the first 120a and second parts 120b of the toolguide way 120 are not separated and are connected to each other,constituting a single tool guide way 120. FIG. 125 is a flowchart ofsuch embodiment. In one embodiment, a first part 120a and a second part120b have different internal structures, so a first burr cannot movepast the first part 120a to move along the second part 120b. Morespecifically, the internal structure of the first part 120a of a toolguide way 120 complements the shape of the first burr, and the internalstructure of the second part 120b of the tool guide way complements theshape of the second burr. Moreover, the first burr and the second burrdiffer with respect to one or more of the following: length of a neck203, thickness of a neck 203, number of guide projections 208, 210,shape of guide projections 208, 210, size of guide projections 208, 210,and other considerations. The first 120a and second parts 120b can alsohave various structures that correspond to those of their respectiveburrs. Accordingly, in an embodiment, the first part 102a canaccommodate the first burr, but the second part 120b cannot accommodatethe first burr, and only the second burr can enter and move along thesecond part 120b. In other embodiments, first 120a and second parts 120bof a tool guide way 120 can have the same internal structure so that afirst burr can pass through a middle or intermediate tool hole 124a andmove along the second part 120b as well.

Guide grooves

Referring to FIGS. 39, 44, 69A, and 69B, in an embodiment of theinvention, each tool guide way 120 has guide grooves 132, 134 to guide aburr 200. Guide projections 208, 210 of a burr are inserted into andmove along their corresponding guide grooves 132, 134. In someembodiments, the distance between guide grooves 132, 134 is constantthroughout a tool guide way. Therefore, in an embodiment with apreparation guide device 100 that has two guide grooves 132, 134, thethickness of a top wall 116 near the tool guide way need not be uniform.However, in other embodiments as shown in FIGS. 27-30, the thickness ofa top wall 116, that is, the distance between a top supporting surface129 and the bottom supporting surface 130 is kept uniform.

Sidewall Entrance for Burrs

In an embodiment as shown in FIGS. 66 and 67, a sidewall has an entrance125 for burrs. The entrance 125 and tool guide way 120, where cutting ofteeth occurs, are connected by a non-cutting access way 1202. A burr 200enters through the entrance (125), is guided by the non-cutting accessway 1202, and after cutting teeth, exits through the same entrance 125by passing back through the non-cutting access way 1202.

Cutting Three or More Side Surfaces using a Single Tool Guide Way

Referring to FIGS. 66-74, in an embodiment, a preparation guide 100 hasa single tool guide way for cutting three or more side surfaces of asingle tooth. In addition, such preparation guide device 100 has anadditional single tool guide way that is configured to cut four sidesurfaces of a single tooth. A first tool guide way 120 is formed on atop wall 116 to be placed over a second molar. The first tool guide way120 is configured to guide a burr to cut the following surfaces of asecond molar: the buccal surface, the entire proximal surface closest tothe missing tooth, a portion of the proximal surface farther from themissing tooth, and the lingual surface. In some embodiments, the burr200 enters through an entrance 125, travels through the non-cuttingaccess way 1202, and is inserted into the tool guide way 120. The burrmoves along the tool guide way 120 and cuts the buccal surface, entireproximal surface closest to the missing tooth, a portion of the proximalsurface farther from the missing tooth, and the lingual surface. Afterall the cutting is completed, the burr travels back through thenon-cutting access way 1202 and exits through the entrance 125.

Still referring to FIGS. 66-74, in an embodiment, the preparation guidedevice 100 has a tool guide way configured to cut three or more sidesurfaces of two or more teeth. A second tool guide way 120 is formed onthe top wall 116 to be placed over the first and second premolars. Thesecond tool guide way 120 is configured to guide a burr to cut sidesurfaces of the first and second premolars. Although buccal surfaces canalso be cut to engage a prosthesis, the amount of buccal surfaces cutcan be reduced for aesthetic reasons if the proximal surface, lingualsurface, and a portion of the opposite proximal surface providesufficient retention force.

Vertical Tool Entrance Hole

In an embodiment as shown in FIG. 75A, a preparation guide device 100has a tool hole 124 that allows a projected structure 1102 to beinserted in a top-down direction. If a burr entrance is designed in suchmanner, a sidewall 110 need not have a gap, and thus the preparationguide device 100 can become more stable, and can well maintain the burrin position during cutting.

In an embodiment as shown in FIG. 75B, a preparation guide device 100has tool holes 124 located on one side of a preparation guide device. Anon-cutting access way 1202 from each tool guide way 120 extends to oneend of the preparation guide device, and tool holes 124 are formed atthis end. The tool holes 124 are located on the end of the preparationguide device closer to the front of the mouth when the preparation guidedevice is installed, that is, the end by the incisors. Some patients arenot able to open their mouths widely, but even for such patients, thefront of the mouth opens more than the rest. Placing tool holes 124 nearthe front of the mouth, as in the embodiment, allows a burr to beinserted at the front of the mouth and can then move along the toolguide way 120, thus not requiring patients to open their mouths as wide.

Although each tool guide way 120 of an embodiment as shown in FIG. 75Bhas a separate non-cutting access way with separate tool holes 124, inother embodiments, as shown in FIG. 75C, non-cutting access ways 1202 ofdifferent tool guide ways 120 can converge and share a single toolentrance hole 124.

Another Embodiment of a Vertical Tool Entrance Hole

An embodiment of the invention as shown in FIG. 79 has a similar shapeas the embodiments shown in FIGS. 66-74 and is for cutting a secondmolar, a first premolar, and a second premolar. The main differencebetween the preparation guide devices 100 of these embodiments is thatthe tool guide way 120 shown in FIG. 79 has tool holes 124 at both ends.Such embodiment does not include a separate non-cutting access way 1202or non-cutting guide section that guides the burr to the start point forcutting after it is inserted into the tool hole 124. Such embodimentsinclude cases where a non-cutting region is included between the toolhole 124 and the cutting start point in the tool guide way 120, butwhere the distance is so short (e.g., diameter of the cutting head ofthe burr) that the region cannot be called a separate non-cutting accessway 1202 or non-cutting guide section. In such embodiments, the burr canstart cutting teeth almost immediately after it is inserted through thetool hole 124 and enters the tool guide way.

Referring to FIGS. 79A and 89, in one embodiment of the invention, atool guide way 120 for the second molar has two tool holes 124 at eachend of the tool guide way for the burr 20 to enter. The tool holes 124are located inside the sidewall 110. In some embodiments, the burr 200is inserted into one tool hole 124 and moves along the tool guide way120, cuts side surfaces, and exits from the tool guide way 120 through adifferent tool hole 124.

In the foregoing embodiments, the tool hole 124 on the buccal surfaceside is used as the entrance, and the tool hole 124 on the lingualsurface side is used as the exit. In other embodiments, the tool hole124 on the lingual surface side can be used as the entrance, and thetool hole 124 on the buccal surface side can be used as the exit. In yetother embodiments, a single tool hole 124 can be provided for the toolguide way 120 and be used as both an entrance and an exit.

Still referring to FIG. 79A, an in embodiment, the second tool guide way120 is formed on the top wall 115 to be placed over first and secondpremolars. The second tool guide way 120 is formed to guide a portion ofthe side surface of the first and second premolars. In an embodiment,the second tool guide way 120 has tool holes 124 at both ends for theburr 200 to enter. These tool holes 124 are located inside the sidewalls110. The burr 200 enters through one of these tool holes 124, movesfollowing the tool guide way 120, and exits through a different toolhole 126.

Marking the Travel Direction of a Burr and Other Information

According to an embodiment of the present invention, the preparationguide device 100 can include signs or indications that provideinformation to dental practitioners. For example, referring to FIG. 89,the preparation guide device of an embodiment has signs 136 thatindicate the direction in which a burr should travel. Although notillustrated, in some embodiments, signs indicating whether a tool hole124 is an entrance or an exit can be included. In some embodiments, suchsigns 136 are placed where they are easily seen by a dentalpractitioner. For example, in some embodiments, signs are provided onthe top. In some embodiments, signs can be raised or recessed and can bein color so that it stands out from the background. In some embodiments,signs 136 that indicate the travel direction of the burr 200 can includevarious types of icons, such as an arrow as shown. In an embodiment, thedental practitioner inserts the burr 200 into the tool hole 124 and cutsteeth by rotating and moving the burr 200 in the direction of the arrow136.

In one embodiment, when a dentist moves a burr along a tool guide waywhile grasping a hand piece coupled to the burr, the dentist can pushthe hand piece away from his/her body to move the burr. The burr can bemoved by way of pushing the hand piece through the entire portion of thetool guide way or a certain portion of the tool guide way. In anotherembodiment, the dentist can pull the hand piece toward his/her body tomove the burr. In a certain embodiment, the dentist can apply a force tothe hand piece from left to right to move the burr. In an alternativeembodiment, the dentist can apply a force to the hand piece from rightto left to move the burr.

Rotational Direction of a Burr

In an embodiment as shown in FIG. 89, a burr 200 rotatescounterclockwise 137 as viewed from the shank 202 of the burr towardsthe cutting head 204. To be more precise, the burr 200 is rotated sothat the tangential direction at the contact point between the cuttinghead 204 and teeth is opposite from the travel direction of the burr200. In an embodiment, most particles of cut teeth pop out towards thetangential direction 138. This is to prevent particles from blocking theburr 200. However, the invention is not limited as such, and in otherembodiments, the tangential direction and the travel direction at thecontact point of the burr 200 and teeth can be the same.

Structure of Tool Holes for Burrs

Referring to FIGS. 89 and 90, in an embodiment, the tool hole 124 islocated at the end of the tool guide way 120. The tool hole 124 has atop opening 140 and a bottom opening 142. In an embodiment, the size ofthe top opening 140 is large enough for the cutting head 204 of the burr200 and the guide projections 208, 210 to pass through. In anembodiment, the size of the bottom opening 142 is large enough for thecutting head 204 of the burr 200 to pass through but not large enoughfor the lower guide projections 210 to pass through. In an embodiment, astopper 144 is located near the bottom opening 142 to prevent the lowerguide projections 210 from moving down further.

In some embodiments, when the stopper 144 stops the lower guideprojection 210, the upper guide projection 208 is situated at the heightof the upper guide groove 132, and the lower guide projection 210 issituated at the height of the lower guide groove 134. Therefore, whenthe burr 200 is stopped from moving down further due to the stopper 144,the burr 200 can be rotated and moved towards the tool guide way 120 asthe guide projections 208, 210 are inserted into the groove to movealong the tool guide way.

Referring to FIG. 91, in an embodiment, the top opening 140 and thebottom opening 142 of tool holes 124 are large enough to allow the burr200, the cutting head 204, and the guide projections 208, 210 to passthrough. The stopper 146 is located below the tool hole 124 and isconfigured such that a terminal end of the cutting head 204 is stopped.In some embodiments, the stopper 146 is located at a point where theguide projections 208, 210 and the guide groove are aligned, but thepresent invention is not limited to such.

Anti-TitlingAnti-tilting Structures

As the burr 200 moves along the path provided by a tool guide way 120and cuts teeth, the burr 200 can tilt from its ideal axis of rotation201. Tilting can occur in various directions. Any such directionincludes a first tilting component in the direction of the travel of theburr 200 along the tool guide way 120 and a second tilting component inthe plane perpendicular to the direction. These tilting components canbe substantially reduced by using complementary shapes and structuresfor the tool guide way 120 and the burr 200. Factors for reducingtilting can include the length of the burr's neck 203, diameter of theneck 203, number of guide projections 208, 210, shape of guideprojections 208, 210, size of guide projections 208, 210, position ofguide projections 208, 210, length of guide surfaces 128 facing eachother in the tool guide way 120 that corresponds to the aforementionedconfigurations, width of guide surfaces 128, number of guide grooves,shape of guide grooves, size of guide grooves, and position of guidegrooves.

One embodiment includes a tilting prevention structure located at theterminal portion 210 of the cutting head 204 of the burr 200. As shownin FIG. 92 FIGS. 92A-92B, the burr 200 includes a cylindrical projection212 that extends vertically from the terminal end of the cutting head204. In this embodiment, the diameter of the cylindrical projection 212is smaller than the diameter of the cutting head 204. Thus, an elevation214 is formed between the cylindrical projection 212 and the cuttinghead 204. In this embodiment, no abrasives or cutting edges are formedaround the exterior of the cylindrical projection 212. Therefore, theexterior of the cylindrical projection 212 moves while in contact withuncut surfaces of teeth, and the burr does not move in the indicateddirection 216 during cutting, thus preventing tilting. During suchprocess, teeth themselves become guide surfaces to guide the burr 200.In another embodiment, abrasives or cutting edges can be formed aroundthe elevation 214.

Cutting Margin Line

As the burr 200 moves along the tool guide way 120, a terminal cuttingportion of the cutting head 204 cuts tooth as far as it can reach,forming a boundary line (cutting margin line) between cut portions anduncut portions. Prostheses are produced such that they can reach and beengaged onto the cutting margin line. Referring to FIG. 24, oneembodiment includes a preparation guide device 100 and burr 200configured such that the terminal cutting portion of the cutting head204 moves along the gingival line. In such cases, the cutting marginline on tooth either coincides or nearly coincides with the gingivalline. In contrast, in the embodiment illustrated in FIG. 92B, the end ofthe cutting head 204 moves along a line located between the survey line84 (or cervical ridge line) and the gingival line. In such cases, thecutting margin line on tooth can easily be seen because it is not on thegingival line. In other embodiments, the preparation guide device 100and the burr 200 can be configured such that the terminal cuttingportion of the cutting head 204 moves above the survey line 84 alongsome portions of the tooth and below the survey line 84 along otherportions. In addition, although not shown, a preparation guide 100 andburr 200 can be configured such that the terminal cutting portion of thecutting head 204 moves below the gingival line. In such cases, thecutting margin line of tooth can be hidden under portions of the gum.

Cut Portions without any Substantial Undercuts

If cutting is solely dependent on a dental practitioner's hand movement,an undercut can result from cutting. However, in one embodiment of theinvention, there is no noticeable undercut on the cut portions of theteeth as viewed along the axis of insertion of the prosthesis. In otherwords, no undercut is present in the portion where the prosthesis is tobe engaged, as viewed along the intended axis of insertion of theprosthesis. Referring to FIGS. 92A-92E, when viewed along theprosthesis's axis of insertion 76, the cut portion of teeth is eithergenerally parallel to the axis of insertion 76 or is sloped such that ittapers slightly towards the occlusal surface.

Sloped Angle of a Cut Surface

In one embodiment of the invention, the angle αbetween the cut surfaceof teeth and the axis of insertion 76, 78 of the prosthesis 50 rangesfrom about 0° to about 3°. In one embodiment, the angle αcan be about0.1°, about 0.2°, about 0.3°, about 0.4°, about 0.5°, about 0.6°, about0.7°, about 0.8°, about 0.9°, about 1°, about 1.1°, about 1.2°, about1.3°, about 1.4°, about 1.5°, about 1.7°, about 1.9°, about 2°, about2.3°, about 2.7°, about 3°, about 3.5°, or about 4°. In otherembodiments, the angle can be within the range of any two of theaforementioned angles. The aforementioned angles are much less than theangle typically formed by cutting without a preparation guide device,which ranges from about 6° to about 10°. It is also possible to cut atan angle of about 4°, about 5°, about 6°, about 7°, about 8°, about 9°,about 10°, about 11°, about 12°, about 13°, about 14°, or about 15°using the preparation guide device. Here, the angle can also be withinthe range of any two of the aforementioned angles.

In one embodiment, the angle αbetween the cut surface 80 and the(intended) axis of insertion 76 of the prosthesis 50 is either constantthroughout all cut portions or is substantially the same. In otherwords, the angle αis the same or substantially the same at any locationwithin any cut surface of a single tooth. In this context, substantiallysimilar means that although the angle αis slightly different fromlocation to location, distribution from the intended angle is about ±5%,about ±6%, about ±7%, about ±8%, about ±9%, about ±10%, about ±11%,about ±12%, about ±13%, about ±14%, about ±15%, about ±16%, about ±17%,about ±18%, about ±19%, about ±20%, about ±21%, about ±22%, about ±23%,about ±24%, about ±25%, or is within the range of any two of theaforementioned numbers.

Tapered Slope of the Cutting Head

In embodiments, the cutting head 204 of the burr 200 is tapered towardsthe terminal end. The tapered angle, or the angle β between the burr'saxis of rotation and the cut surface of teeth, is substantially similarto the angle α. In other embodiments, the sloped angle αof the cutsurface 80 may not be constant throughout the cut surface 80. Eventhough the tapered angle β of the burr is constantly maintained alongthe exterior surface of the burr, the sloped angle α of the cut surface80 may be of a different angle than β if the slope of the guide surface128 of the guide slot of the tool guide way 120 is varied with referenceto the prosthesis's axis of insertion.

Depth/Thickness of Cut Teeth

In various embodiments of the invention, cut surfaces can have slopedangles ranging from about 0° to about 3°. Accordingly, the depth orthickness of a cut may be smaller compared to traditional methods ofcutting without a preparation guide device. The preparation guide devicein one embodiment of the invention allows the prosthesis to be engagedafter cutting only the enamel layer of teeth. When cutting just theenamel layer, even those procedures that require cutting substantialportions of teeth (e.g., for crowns or cutting three or four surfaces ofa tooth) may be undertaken without anesthesia. In another embodiment, itis possible to cut a portion of the dentin layer as well, although it ispreferable to cut only within the enamel layer.

According to one embodiment of the invention, the depth (thickness) ofthe cut in parts where the most amounts of teeth are cut is markedlyless than cutting by other methods. More specifically, as viewed alongthe intended axis of insertion of the prosthesis, the depth of cuttingnear the cervical ridge line or survey line is about 0.1 mm, about 0.2mm, about 0.3 mm, about 0.4 mm, about 0.5 mm, about 0.6 mm, about 0.7mm, about 0.8 mm, about 0.9 mm, about 1.0 mm, about 1.1 mm, about 1.2mm, about 1.3 mm, about 1.4 mm, about 1.5 mm, about 1.6 mm, about 1.7mm, about 1.8 mm, about 1.9 mm, about 2.0 mm, about 2.1 mm, about 2.2mm, about 2.3 mm, about 2.4 mm, about 2.5 mm, about 2.6 mm, about 2.7mm, about 2.8 mm, about 2.9 mm, or about 3.0 mm. Alternatively, thedepth of cutting near the cervical ridge line or survey line can also bewithin the range of two of the aforementioned numbers. Preferably, thedepth of cutting is about 0.5 mm, about 0.6 mm, about 0.7 mm, about 0.8mm, about 0.9 mm, about 1.0 mm, about 1.1 mm, about 1.2 mm, about 1.3mm, about 1.4 mm, about 1.5 mm, about 1.6 mm, or within the range of twoof the aforementioned numbers.

Thickness of Prosthesis Fixing Portions

Because the depth of cut is smaller, the thickness of the fixingportions 52 of the prosthesis 50 to be engaged on such locations canalso be substantially smaller. When materials that allow thin fixingportions are used, the depth of cutting can be even smaller. Thethickness of the prosthesis that is engaged over cut surfaces 80 ismeasured from the same location as for measuring the depth of the teethcut, namely from the cervical ridge line or survey line. The thicknessof the prosthesis can be about 0.1 mm, about 0.2 mm, about 0.3 mm, about0.4 mm, about 0.5 mm, about 0.6 mm, about 0.7 mm, about 0.8 mm, about0.9 mm, about 1.0 mm, about 1.1 mm, about 1.2 mm, about 1.3 mm, about1.4 mm, about 1.5 mm, about 1.6 mm, about 1.7 mm, about 1.8 mm, about1.9 mm, about 2.0 mm, about 2.1 mm, about 2.2 mm, about 2.3 mm, about2.4 mm, about 2.5 mm, about 2.6 mm, about 2.7 mm, about 2.8 mm, about2.9 mm, or about 3.0 mm or within the range of two of the aforementionednumbers. Preferably, the thickness of the prosthesis is about 0.5 mm,about 0.6 mm, about 0.7 mm, about 0.8 mm, about 0.9 mm, about 1.0 mm,about 1.1 mm, about 1.2 mm, about 1.3 mm, about 1.4 mm, about 1.5 mm,about 1.6 mm, or within the range of two of the aforementioned numbers.

Interior Side Surfaces of a Prosthesis Fixing Portion

The three-dimensional shape and size of interior side surfaces 59 of theprosthesis 50 fixing portion 52 is precisely complementary to thethree-dimensional shape and size of cut surfaces 80 formed on anabutment tooth. Referring to FIG. 92D, such interior surfaces 59 areangled with reference to an intended axis of insertion 76 of theprosthesis. Such sloped angle γ is substantially similar to the angle α.In other embodiments, the angle γ can be slightly larger than α.

Scope of Error

Errors are inevitable in manufacturing and cutting procedures. However,cutting teeth using a preparation guide device and burr according toembodiments of the invention lead to substantially similar results asthe prospective cut surface images prepared by CAD/CAM systems duringthe design stages of the preparation guide device. Comparisons of dataobtained from three-dimensional digital scans of actually cut teeth withdata of simulated prospective cut surface images using CAD/CAM systemsshow that the data obtained from actually cut teeth err on average byabout 20μ, about 40μ, about 60μ, about 80μ, about 100μ, about 120μ,about 140μ, about 160μ, about 180μ, about 200μ, about 220μ, about 240μ,about 260μ, about 280μ, about 300μ, or within the range of two of theaforementioned numbers.

If an error occurs repeatedly under the same conditions (materials ofthe preparation guide device, manufacturing tools used for thepreparation guide device, materials of the burr, etc.), such error canbe greatly reduced by undergoing subsequent corrective measures. Whetheror not subsequent correction measures have been taken, the average scopeof error is preferably under about 100μ or, to be more specific, about20μ, about 40 μ, about 60μ, about 80μ, or about 100μ. Also, this averagescope of error can be within the range of any two of the aforementionednumbers. When obtaining data for actually cut teeth, the burr 200 mustnot be forced to tilt within the tool guide way 120, and the cuttingprocess must be performed to minimize any error. Considering the factthat the shape of the actually cut teeth is obtained by cutting aminimal amount and by not excessively changing its original shape, thescope of error mentioned above is even more unexpected.

Shape of Prosthesis's Fixing Portion

In one embodiment of the present invention, the fixing portion 54 of theprosthesis 50 does not need to have a ring shape. As shown in FIGS. 71and 72, the fixing portion 54 of the prosthesis to be engaged on a molaris open on one side. In the embodiment shown, the fixing portion 54 tobe engaged on a molar includes a lingual portion 542 to engage thelingual surface and a buccal portion 544 to engage the buccal surface,wherein the two portions face each other. The lingual portion 542 andbuccal portion 544 include interior surfaces that face each other. Asthe fixing portion 54 engages a molar, the molar fits within these twointerior surfaces facing each other, creating retention force to fix theprosthesis. Moreover, the proximal portions 546, 548 engaged on the twoproximal surfaces of a molar also face each other to keep the prosthesisin position.

On the other hand, as shown in FIGS. 71 and 72, the fixing portion 55 ofa second premolar does not include a portion to be engaged on the buccalsurface. Nonetheless, side portions 556, 558 are positioned to face eachother in such case as well, and the interior surfaces of these sideportions 556, 558 face each other. As described above, a second premolaris fit between these two interior surfaces facing each other, creatingretention force to fix the prosthesis. The fixing portion 56 for a firstpremolar has a similar design wherein side portions 566, 568 face eachother. The interior surfaces of these side portions 566, 568 face eachother as well. As described above, a first premolar is inserted betweenthese two interior surfaces that face each other, creating retentionforce to fix the prosthesis. In the illustrated embodiment, theretention force of the first premolar and the retention force of thesecond premolar in combination provide sufficient retention effects.

Preservation of Occlusal Surfaces

Dental procedures that employ a preparation guide device and aprosthesis as shown in FIGS. 66-74 can preserve the occlusal surfaceswithout cutting thereof. In one embodiment shown, the amount cut can beprecisely controlled using a preparation guide device. By employing apreparation guide device as shown in one embodiment, sufficientretention force between the prosthesis and teeth can be maintained whilecutting only a minimum amount of side surfaces. This allows the teeth tosubstantially maintain their original shape and strength.

On the other hand, traditional methods of cutting that cut large amountsresult in smaller remains of teeth, requiring thicker crowns in order toincrease tensile strength and endure the amount of force exerted fromchewing. To accomplish this, cutting of occlusal surfaces is necessary.In addition, if the cut amount is so large as to cut into the dentinlayer, cavities may spread along the boundary between the prosthesis andteeth even if covered with prosthesis. To minimize such risk,traditional dental procedures require cutting of occlusal surfaces andcovering the whole occlusal surface with a crown.

However, if minimally invasive preparation (or cutting) is performed asshown in the embodiment, cutting of occlusal surfaces is not alwaysnecessary. In addition, because cutting is performed only within theenamel layer if possible, there is less risk of cavities spreading tothe dentin through the boundary surface between the teeth and theprosthesis. Thus, occlusal surfaces are not cut in the illustratedembodiment. Moreover, the prosthesis does not need to cover the entireocclusal surface. However, other embodiments can include cuttingportions of the occlusal surfaces to engage the prosthesis.

As shown in FIGS. 71-74, the prosthesis 50 includes an extendedprotruding portion (inlay portion) 552 that extends and protrudes from aproximal portion at the top of the fixing portion 54. Such extendedprotruding portion 552 fits tightly within a nonfunctional groovebetween the cusps of the occlusal surface of an abutment tooth 70 toincrease retention force of the prosthesis. In such case, thenonfunctional groove can either be preexisting and natural or can beartificially formed by using, for example, a preparation guide device.When a groove is artificially formed, it is called an inlay bridge.

Preservation of Contact Points

Prior to cutting, an abutment tooth 70 and a proximal tooth 72 come intocontact at a contact point. In one embodiment of the invention, theabutment tooth is cut without damaging this contact point such thatfunctions of the abutment tooth prior to cutting are not lost. Inembodiments, the whole contact surface between an abutment tooth 70 andproximal tooth 72 or at least the contact point within the contactsurface is not cut during the cutting process. As shown in FIGS. 71-74,although the fixing portion 54 of the prosthesis on a first premolar isin contact with a portion of the mesial surface from the lingual surfaceof the first premolar, the prosthesis does not cover the whole mesialsurface, thus retaining the contact point between the first premolar anda canine.

In addition, in one embodiment as shown in FIGS. 71-74, the fixingportion 54 of the prosthesis 50 on a second molar includes a first wingthat extends from an artificial tooth 52 and covers the second molar'smesial and buccal surfaces. The terminal end thereof extends to thedistal surface or the transitional region between the buccal surface anddistal surface. A second wing on the other side extends from theartificial tooth 52 and covers the second molar's mesial and lingualsurfaces. The terminal end thereof extends to the distal surface or thetransitional region between the lingual and distal surfaces. Thus, thefixing portion 54 may preserve the contact point between a second molarand a wisdom tooth (not shown). In the method of cutting andconfiguration of prosthesis according to one embodiment of the presentinvention, such preservation of contact points is possible becausesufficient retention force may be provided without covering the entiretyof side surfaces.

Materials for and Manufacturing of Preparation Guide Devices

In one embodiment of the invention, the burr 200 spins at high speeds(for example, 3,000-400,000 rpm) while cutting teeth. Because thepreparation guide device 100 is in contact with the neck 203 of the burr200 rotating at high speeds, it should be made of a material that is noteasily damaged by physical contact and is not easily transformed byfrictional heat. The material must also be biocompatible. For example,plastic resin, ceramic, or metallic materials may be used. Morespecifically, materials such as gold, gold alloys, titanium, titaniumalloys, glass, and high molecular compounds may be used. If the materialof the preparation guide device is transparent or translucent, theinstallation status or cutting procedure may easily be observed.

A preparation guide device 100 can be manufactured by using precisemanufacturing processes via a CNC Machining Center or by using additivemanufacturing processes via three dimensional printing orstereolithography. Methods of manufacturing a preparation guide device100 of the invention are not limited to such means. Although thepreparation guide device 100 is made of a single material in theembodiment mentioned above, the preparation guide device 100 can be madeof two or more materials as well. For example, portions of thepreparation guide device 100 surrounding the tool guide way 120 can bemade of the above-described materials, and the rest can be made of othermaterials.

Embodiment as Shown in FIGS. 3, 4, 6-9, and 24

Referring to FIGS. 3, 4, 6-9,12, and 24, a preparation guide device 100according to one embodiment of the invention includes a tool guide way120 within each of two guide portions 104 to allow for cutting of twoteeth. The two guide portions 104 are connected to form a single piece.While the embodiment as shown illustrates a structure wherein the guideportion 104 is engaged directly on an abutment tooth 70, anotherembodiment may include a structure wherein an additional installationportion 102 engages a proximal tooth 72 adjacent to the abutment tooth.

The tool guide way 120 has a looped curve shape to allow for processingall side surfaces at once. The top wall 116 of the guide portion 104includes a central section 1162 and a surrounding section 1164 dividedby the tool guide way 120. The central section 1162 and surroundingsection 1164 are connected by an appropriate number of rod-shapedconnectors 1166 to prevent the central section 1162 from becomingseparated. In the embodiment shown, the sidewall 110 extends below thesurvey line.

In one embodiment shown, a non-cutting access way 1202 of the loopedtool guide way 120 extends beyond the sidewall 110. The end of thisnon-cutting access way 1202 becomes a tool entrance 125, which islocated beyond the sidewall 110. A burr 200 enters through the entrance125 and passes the non-cutting access way 1202 to reach the tool guideway 120. A burr 200 moves along the tool guide way 120 to cut sidesurfaces of teeth. A burr 200 may also cut the connector 1166 whilecutting side surfaces to move further along the tool guide way 120. FIG.24 shows an embodiment of cutting side surfaces using a preparationguide device 100. As shown in FIGS. 14, 19, 20, and 44, a tool entrance125 may be located on the sidewall 110 itself without a non-cuttingaccess way 1202.

Embodiment as Shown in FIG. 5

The preparation guide device 100 according to one embodiment, as shownin FIG. 5, includes two connectors 1166. A resulting tool guide way 120includes two sections divided by the connectors 1166. Each section hasits own non-cutting access way 1202 in the tool guide way 120. Inaddition, each non-cutting access way 1202 has its own tool entrance125. A preparation guide device 100 of such structure allows for cuttingall side surfaces of teeth without having to cut the connector(s) 1166.The size, structure, location, and number of connector(s) 1166 can bevaried according to the shapes of teeth and burr.

Connector(s)

The example in FIGS. 3-9 includes a rod-shaped connector 1166. When aconnector 1166 extends across the guide slot, it is still possible tocut teeth surfaces below the connector 1166 without damaging theconnector 1166 if the diameter of a cutting head 204 of a burr 200 issufficiently large. In other words, if the diameter of the cutting head204 of a burr 200 is larger than the width of the connector 1166 whencutting portions beneath the connector 1166, the cutting head 204 of theburr can reach surfaces of a tooth beneath the connector 1166. Thus, theconnector 1166 does not obstruct the process of cutting. In suchembodiments, the number of tool entrances 125 is equal to the number ofsections in the tool guide way 120 formed by connectors 1166 mentionedabove.

The width of the connector 1166 can vary according to the material usedfor the preparation guide device 100. If the material of a preparationguide device 100 is strong, the width of the connector 1166 can berelatively narrow compared to a preparation guide device 100 made fromrelatively weak material. A connector(s) 1166 is not necessary if thetool guide way 120 does not have a looped curve shape, for example, ifit is linear or sectioned.

Embodiment as Shown in FIGS. 10 and 11

A preparation guide device 100 as shown in FIGS. 10 and 11 includes asidewall 110 that either does not extend or extends only slightly belowthe survey line. In such an embodiment, whether the preparation guidedevice 100 is properly engaged on an abutment tooth 70 can easily bechecked by observing the boundary of the survey line or by using aprobe. Therefore, it is not necessary to have a separate blocked-outportion 118 that opens up a portion of the sidewall 110 to check whetherthe preparation guide device 100 has been properly engaged. In thisembodiment, the cutting procedure can also be seen under the preparationguide 100.

Flow of Cooling Water

In one embodiment, cooling water can flow from the hand piece 230through a guide slot and tool entrance 124 etc. of a tool guide way 120,for example, and through the interior of a guide portion 104 to exitthrough a blocked-out portion 118 below the survey line (see FIGS. 94B,95B, 99B, and 100B). In other embodiments, cooling water can flowthrough an additional hole(s) or some other opening. The size of suchopening(s) can be varied according to the amount of cooling water andrigidity of the preparation guide device 100.

Embodiment as Shown in FIGS. 12 and 13

An entrance for a burr 200 is located on the interior of a sidewall 110,that is, as a hole 124 on the top wall 116. Because a notch is notformed on the sidewall 110 according to such configuration,transformation of the preparation guide device 100 is less likely.

Embodiment as Shown in FIGS. 14-17

A preparation guide device 100 according to one embodiment as shown inFIG. 14 includes a burr 200 entrance located on a sidewall 110 and atool guide way 120 formed along only a portion of a side surface of atooth. The preparation guide device 100 of one embodiment as shown inFIG. 15 includes a tool guide way 120 formed along a sidewall 110 toallow cutting of occlusal surfaces. The preparation guide device 100 ofone embodiment as shown in FIG. 16 includes a tool guide way 120 formedon a sidewall 110 to allow installation of strip-shaped grooves onbuccal or lingual surfaces. The preparation guide device 100 of oneembodiment as shown in FIG. 17 includes a guide hole located on a topwall 116 to form a rest seat on occlusal surfaces.

Embodiment as Shown in FIG. 18

The preparation guide device 100 of one embodiment as shown in FIG. 18includes a tool guide way 120 that allows for continuous cutting oflingual or buccal surfaces of multiple teeth at once. By engaging asingle-body prosthesis 50 on three teeth after such cutting, an unstabletooth (for example, the middle tooth) can be fixed in place.

Embodiment as Shown in FIGS. 19-21

The preparation guide device 100 according to one embodiment as shown inFIGS. 19-21 includes a tool guide way 120 that allows for cutting ofside surfaces of multiple anterior teeth. A preparation guide device 100as shown in FIG. 19 includes a tool entrance located on a sidewall 110.A preparation guide device 100 as shown in FIG. 21 includes a toolentrance located on a top wall 116.

Embodiment as Shown in FIGS. 22 and 23

The preparation guide device 100 according to one embodiment as shown inFIGS. 22 and 23 includes a tool guide way 120 formed on a sidewall 110of lingual surfaces to allow cutting of lingual surfaces of multipleanterior teeth. In one embodiment as shown in FIG. 23, the preparationguide device 100 includes two tool guide ways 120 per anterior tooth toform two cavities per anterior tooth. As such, two or more tool guideways 120 may be engaged on a single tooth as needed. The preparationguide device 100 of one embodiment as shown in FIG. 23 includes one toolguide way 120 per anterior tooth to allow for cutting along the cingulumof each anterior tooth.

Embodiment as Shown in FIG. 24

Referring to FIG. 24, the preparation guide device 100 of one embodimentincludes a tool guide way 120 with vertical curves. In cases where thebottommost section of teeth to be cut is vertically curved along thegum, a tool guide way 120 can also include vertical curves generallyparallel to the curves of the portion to be cut. As shown in FIGS. 25and 26, a tool guide way 120 is configured to follow in parallel thebroken lines showing the path or trajectory of the bottommost point ofthe burr 200. In another embodiment as shown in FIG. 25, the tool guideway 120 is configured without any vertically undulating curves becausethere are no vertically undulating curves along the bottommost path of aburr. On the other hand, when vertically undulating curves exist alongthe bottommost path of the burr, as shown in FIG. 26, a tool guide way120 is installed with vertically undulating curves substantiallyparallel to the vertically undulating curves of the bottommost path ofthe burr. Thus, in the illustrated embodiments, the tool guide way 200is configured according to the shape of the bottommost path of the burr.

In the embodiments illustrated in FIGS. 24, 25, and 26, a guideprojection 207 of the burr 200 moves along above the top support surface129 of the tool guide way 120. Thus, if vertical curves exist at thebottommost path of the burr, the top support surface 129 also includesvertical curves that are substantially parallel. In embodiments whereguide projections 208, 210 move along guide grooves 132, 134, as inembodiments as shown in FIGS. 38 and 39, the guide grooves 132, 134 alsoinclude vertical curves that are largely parallel if vertical curvesexist at the bottommost path of the burr.

On the other hand, in one embodiment as shown in FIG. 24, the tool guideway 120 is configured such that the bottommost end of the burr 200follows the gingival line. In other embodiments, the tool guide way 120can be placed at a vertically higher point or the length of the cuttinghead 204 can be shorter to allow the bottommost end of the burr 200 tomove along a path between the survey line and the gingival line (seeFIG. 108). Thus, once a portion to be cut is determined, the path of theend of the cutting head 204 is determined, and the vertical curves ofthe tool guide way 120 are determined according to the vertical curvesof that path.

As shown in FIG. 24, when the burr 200 cuts teeth 70 while moving alongthe tool guide way 120, the burr 200 moves up and down along the toolguide way's 120 top support surface above a guide projection (or guidegrooves, see FIGS. 31, 32, 33, 38, and 39) following the vertical curvesand cuts teeth. The cut portion of teeth thus formed includes a curvedstep 82 in its bottommost portion, and the shape of the prosthesis 50 isconfigured to accommodate such curved step. In other embodiments, a stepin the bottommost portion may not be formed. Especially in cases wherethe bottommost end of the cutting head 204 is placed between the surveyline and the gingival line, a clear boundary may not be visibledepending on the angle and depth of the cutting.

Various Embodiments of Burrs and Tool Guide Ways

Tilting may occur as the burr 200 cuts teeth while moving along a toolguide way 120. If excessive tilting occurs, cutting of unexpected areasmay result. Also, the amount cut may be more or less than intended. Whensuch errors in cutting occur, the binding of prosthesis 50 and tooth maynot be proper or other complications may develop afterwards. Embodimentsof the invention provide configurations to minimize such tilting.

In one embodiment as shown in FIGS. 27A and 27B, the burr 200 includestwo disc-shaped guide projections 208, 210, wherein one is positionedabove the other. The top guide projection 208 of the burr 200 issupported by and moves along the top support surface 129 of the toolguide way 120, while the bottom guide projection 210 is supported by andmoves along the bottom support surface 130, allowing the burr 200 tomove. FIGS. 9 and 43 show a cutting procedure using such a burr 200.

In one embodiment as shown in FIGS. 28A and 28B, the burr 200 includestwo sphere-shaped guide projections 208, 210, wherein one is positionedabove the other. As illustrated in FIG. 41, sphere-shaped guideprojections are preferred for moving along a tool guide way 120 withvertical curves. Because the contact area is small as the burr 200 spinsand moves to cut teeth, tilting of the burr 200 as well as friction isreduced. As shown in FIG. 40, burrs 200 with disc-shaped guideprojections 207 of relatively small diameters can move along smoothlyeven in the presence of slight vertical curves. However, as shown inFIG. 42, burrs 200 with disc-shaped guide projections 207 of largerdiameters may not be able to properly follow a tool guide way 120 withvertical curves. Although such guide projections 207 with largediameters may be advantageous to prevent tilting while moving, movementalong vertically curved portions may be restricted due to strongerfriction with support surfaces of the tool guide way 120.

In one embodiment as shown in FIGS. 29A and 29B, a burr 200 moves alonga tool guide way 120 that includes a guide surface 128 on only one side.In addition, the burr 200 moves along the tool guide way 120 viacontacts between guide projections 208, 210 and the top and bottomcorners of a guide surface 128. If the tool guide way configuration ofsuch embodiment is employed, a central section 1162 or connector 1166 asshown in FIG. 3 is unnecessary. In one embodiment as shown in FIGS. 30Aand 30B, the neck portion 203 of the burr 200 has a small diameter andfits within and moves along the tool guide way 120.

On the other hand, in one embodiment as shown in FIGS. 31A and 31B, theburr 200 includes a single sphere-shaped guide projection 207. Suchguide projection 207 fits within a hemispheric groove of the guidesurface in the tool guide way in order to guide the burr 200. In oneembodiment as shown in FIGS. 32A and 32B, the burr 200 includes anelliptical guide projection 207. The elliptical guide projection 207moves along within the groove of the tool guide way 120 as the burr 200moves along the tool guide way 120.

In one embodiment as shown in FIGS. 33A and 33B, the burr 200 includestwo sphere-shaped guide projections 208, 210. Of the two, the bottomguide projection 210 fits within a groove 131 provided within a guidesurface 128 of the tool guide way 120. The top guide projection 208moves along while being in contact with the top support surface 129 ofthe tool guide way 120.

In one embodiment as shown in FIGS. 34A and 34B, the burr 200 includestwo sphere-shaped guide projections 208, 210. As the burr 200 movesalong a tool guide way 120, the bottom guide projection 210 moves alongwhile in contact with the bottom support surface 130 of the tool guideway 120, and the top guide projection moves along while in contact withthe top support surface 129.

In one embodiment as shown in FIGS. 35A and 35B, the burr 200 includes asphere-shaped guide projection 207 on the top. In addition, the top ofthe cutting head 204 includes a hemispheric shape to function as a guideprojection. As the burr 200 moves along a tool guide way 120, the guideprojection 207 moves along while in contact with the top support surface129 of the tool guide way 120, and the top of the cutting head 204 movesalong while in contact with the bottom support surface 130 of the toolguide way 120.

In one embodiment as shown in FIGS. 36A and 36B, the burr 200 includes asphere-shaped guide projection. The top support surface 129 of a toolguide way 120 includes a groove. As the burr 200 moves along the toolguide way 120, a portion of the sphere-shaped guide projection fitswithin and moves along the groove formed on the top support surface 129of the tool guide way 120. In another embodiment as shown in FIG. 36C,the burr 200 includes two sphere-shaped guide projections 208, 210. Thetop support surface 129 and bottom support surface 130 of a tool guideway 120 each includes a groove. Each guide projection 208, 210 fitswithin and moves along each respective groove. On the other hand, in oneembodiment as shown in FIGS. 37A and 37B, a guide projection 207 moveswhile in contact with the top support surface 129 of the tool guide way120 as the burr 200 moves along the tool guide way 120.

In one embodiment as shown in FIGS. 38A and 38B, the burr 200 includestwo sphere-shaped guide projections 208, 210 of different sizes. Sideguide surfaces 128 of a tool guide way 120 include grooves 132, 134 thataccommodate each guide projection 208, 210. As the burr 200 moves alongthe tool guide way 120, the two guide projections 208, 210 fit withinand move along each groove 132, 134. In one embodiment as shown in FIGS.39A and 39B, the burr 200 includes two sphere-shaped guide projections208, 210 of the same size, and as the burr 200 moves along the toolguide way 120, the two guide projections 208, 210 fit within and movealong each groove 132, 134.

In one embodiment as illustrated in FIGS. 88A and 88B, the burr 200includes two sphere-shaped guide projections 208, 210, wherein one islocated above the other. Guide surfaces 128 on a side of a tool guideway 120 include rectangular grooves 132, 134. The guide projections fitwithin and move along such grooves 132, 134. In such an embodiment, thecontact area between the grooves 132, 134 and the guide projections 208,210 may be smaller than that of embodiments illustrated in FIGS. 38 and39. Accordingly, friction is reduced, allowing for the burr to spin andmove smoothly. In addition to being rectangular, the shape of the groovemay also be of other polygons, such as triangular, trapezoidal, orpentagonal.

Flow of Cooling Fluid

Cooling fluid, such as water, is generally provided to cool the burr 200and teeth during cutting. The flow of such cooling fluid is used notonly to cool the teeth and the burr 200, but is also used to remove cuttooth pieces and particles from the burr.

In one embodiment as shown in FIG. 43, the preparation guide device 100includes holes 170 to allow for such cooling fluids to flow through. Inone embodiment, such hole(s) 170 is located below the survey line. Inother embodiments, as illustrated in FIGS. 11, 13, and 89, a sidewall 10may extend only to the survey line or include a blocked-out portion 118to allow cooling fluid to flow through.

Single Preparation Guide Device for Cutting both Occlusal and SideSurfaces

In cases where an abutment tooth's occlusal and side surfaces both needto be cut, for example, for a crown or crown and bridge prosthesis, asingle preparation guide device may include tool guide ways that allowcutting of both occlusal and side surfaces. In such cases, thepreparation guide device may move relative to the teeth while cuttingocclusal surfaces as the side surfaces are being cut. Then, precisecutting cannot be performed on the occlusal surfaces due to movement ofthe preparation guide device. This is especially the case when thepreparation guide device is placed directly on an abutment tooth or whenthe abutment tooth is not sufficiently supported by adjacent teeth. Inaddition, a tool guide way for occlusal surface may be damaged whilecutting the side surfaces. Even if side surfaces are cut after cuttingan occlusal surface, a tool guide way necessary for cutting the sidesurfaces may already be damaged.

One embodiment of the invention addresses the aforementioned problemsvia strategic positioning of guide slots. A preparation guide device 100as shown in FIGS. 44-54 illustrates such an embodiment. For example, atool guide way 120 for cutting side surfaces may be located on theinside of a tool guide way 120 for cutting an occlusal surface or, inother words, closer to the teeth when viewed from above the occlusalsurface. Then, the tool guide ways 120 for guiding burrs 200 to cutocclusal and side surfaces do not cross each other. In such anembodiment, the side surfaces are cut first, and then the occlusalsurface.

In contrast, a tool guide way 120 for cutting side surfaces may belocated above a tool guide way 120 extending from lingual and buccaldirections for cutting an occlusal surface or, in other words, fartheraway from the teeth when viewed from the side of a side surface. Then,the tool guide ways 120 for guiding burrs 200 to cut the occlusal andside surfaces do not cross each other. In such an embodiment, theocclusal surface is cut first, and then the side surfaces.

The order of cutting different surfaces may vary depending on whetherthe occlusal or side surfaces support the preparation guide device morestrongly. For example, if the side surfaces provide stronger support,then it is advantageous to cut the occlusal surface first and then theside surfaces. However, if the occlusal surface provides strongersupport, then it is advantageous to cut the side surfaces first and thenthe occlusal surface.

Other embodiments of the invention, as shown in FIGS. 80-85, use twopreparation guide devices 1002, 1004 when cutting teeth for crownprosthesis. Such embodiments are discussed in more detail below.

Embodiments as Shown in FIGS. 44-54

According to embodiments as shown in FIGS. 44-54B, both occlusal andside surfaces of an abutment tooth 70 can be cut effectively using asingle preparation guide device 100. In the illustrated embodiments, thetool guide way 120 for cutting side surfaces and the tool guide way 120for cutting occlusal surfaces are configured not to conflict with eachother while cutting teeth 2. This configuration prevents the tool guideways 120 from being damaged while cutting.

FIGS. 44-55B show a preparation guide device 100 used for cutting teethin order to install a crown and bridge prosthesis 50. The preparationguide device 100 has a tool guide way 120 for guiding the burr 200 tocut an occlusal surface and a tool guide way 120 for guiding the burr200 to cut side surfaces. The tool guide ways 120, as explained in theembodiment above, include guide slots located between two guide surfaces128 facing each other. The neck 203 of the burr 200 fits within theguide slot of the tool guide way 120, allowing the burr 200 to movealong the tool guide way 120.

The preparation guide device 100 illustrated above can be installed oncein the patient's mouth and allow cutting of both occlusal and sidesurfaces before being removed.

In the illustrated embodiments, the tool guide way 120 for side surfaceshas a burr entrance that cuts across the sidewall near the adjacenttooth 72 of an abutment tooth 70. The tool guide way 120 for occlusalsurfaces has two distinct tool guide ways per abutment tooth 70. Morespecifically, for each abutment tooth 70, separate tool guide ways existfor cutting a portion of the occlusal surface closer to the cheek andfor cutting a portion of the occlusal surface closer to the tongue. Theocclusal tool guide ways 210 each have a burr entrance 125 located onthe top wall 116 of the preparation guide device 100.

Cutting Occlusal Surfaces before Cutting Side Surfaces

In cases of cutting occlusal surfaces before side surfaces, apreparation guide device 120 is configured such that a tool guide way120 for cutting side surfaces is not damaged by a burr 200 while cuffingan occlusal surface. Due to such structure, the burr 200 remains fullysupported while cutting side surfaces after cutting occlusal surfaces.More specifically, as shown in FIGS. 48B, 50B, and 51B, a tool guide way120 for cutting side surfaces can be located farther from the teeth thanthe projected path of the cutting head 204 of the burr 200 for cuttingocclusal surfaces. In other words, in FIGS. 48B, 50B, and 51B, a toolguide way 120 for cutting side surfaces is located higher and away fromthe tooth. Such structure prevents the tool guide way 120 for sidesurfaces from being damaged by the burr 200 while cutting occlusalsurfaces. In cases where a connector 1166 is placed across the guideslot of the guide way for side surfaces, the connector 1166 can beinstalled at an appropriate location such that it is not cut during thecutting of occlusal surfaces (see FIG. 48B).

A preparation guide devices 100 used for cutting occlusal surfacesbefore side surfaces may also be purposefully designed to damage thetool guide way 120 for occlusal surfaces while cutting side surfaces.This is because the cutting of occlusal surfaces is already complete bythe time side surfaces are cut and the tool guide way 120 for occlusalsurfaces is no longer necessary. Such design allows for partiallynarrower preparation guide devices 100, allowing the guide devices 100to meet necessary size restrictions. When using a preparation guidedevice 100 of such configuration, the user (dental practitioner) must beinstructed to cut the occlusal surfaces before cutting the sidesurfaces.

Cutting Side Surfaces before Occlusal Surfaces

In cases of cutting side surfaces before occlusal surfaces, apreparation guide device 120 is structured such that a tool guide way120 for cutting occlusal surfaces is not damaged by a burr 200 whilecutting side surfaces. Due to such configuration, the burr 200 remainsfully supported while cutting occlusal surfaces after cutting sidesurfaces. More specifically, a tool guide way 120 for occlusal surfacescan be located farther from the teeth than the projected path of thecutting head 204 of the burr 200 for cutting side surfaces. Suchstructure prevents the tool guide way 120 for occlusal surfaces frombeing damaged by the burr 200 while cutting side surfaces.

A preparation guide devices 100 used for cutting side surfaces beforeocclusal surfaces may also be purposefully designed to damage the toolguide way 120 for side surfaces while cutting occlusal surfaces. This isbecause the cutting of side surfaces is completed by the time occlusalsurfaces are cut, and thus the tool guide way 120 for side surfaces isno longer necessary. Such configuration allows for partially narrowerpreparation guide devices 100, allowing the guide devices 100 to meetcertain restrictive limitations in size. When using a preparation guidedevice 100 of such design, however, the user (dental practitioner) mustbe instructed to cut the side surfaces before cutting the occlusalsurfaces.

Checking the Installation Status of a Preparation Guide Device

As shown in FIGS. 49 and 54, whether a preparation guide device has beenproperly engaged on the patient may be checked. The installation statusof the preparation guide device can be checked either by observation, asshown in FIG. 49, or via use of a probe 250, as shown in FIG. 54.

Embodiment as Shown in FIG. 56

According to one embodiment as shown in FIG. 56, a burr entrance forentering a tool guide way of the preparation guide device 100 forcutting side surfaces is located on the top wall in the form of a hole.As described above, such entrance structure does not have an opening inthe sidewall, allowing the preparation guide device 100 to retainstability over teeth.

Embodiments as Shown in FIGS. 57-65

In one embodiment, as shown in FIGS. 63-65, the prosthesis 50 includesfixing portions 54 to be engaged on abutment teeth 70 on both sides of amissing tooth and an artificial tooth 52 located between the two fixingportions 54. As shown in FIG. 65, the two fixing portions 54 eachcomprise fixing projections 58 that can be inserted into and fixedwithin arc-shaped or horseshoe-shaped prosthesis fixing grooves 86formed on each anterior abutment tooth 70 along the cingulum. In oneembodiment of the invention, the fixing portion 54 is made of metallicmaterials, such as gold, gold alloy, titanium, or titanium alloy, and anartificial tooth 52 is made of an appropriate material for artificialteeth, such as gold or zirconia. In other embodiments, the fixingprojection can be made of ceramic material, such as zirconia, and not ofmetallic material.

In one embodiment, fixing projections are formed on the prosthesis andgrooves are formed on the teeth in order to fix the prosthesis. In orderto obtain sufficient retention force when fixing the fixing projectionsand the grooves, the grooves must be precisely prepared. Morespecifically, the three-dimensional shape and size of fixing projections58 formed on the fixing portions 54 of the prosthesis 50 must beprecisely complementary to the three-dimensional shape and size of theprosthesis fixing grooves 86 formed on an abutment tooth. When viewedalong the intended axis of insertion of the prosthesis 50, all cutsurfaces that form the sidewalls of the prosthesis fixing grooves 86must be consistent with or substantially consistent with the intendedaxis of insertion. Similarly, when viewed from the intended axis ofinsertion of the prosthesis 50, all cut surfaces that form the sidewallsof a fixing projection 56 58 must be consistent with or substantiallyconsistent with the intended axis of insertion. Also, when a fixingprojection 56 58 is inserted into and fixed upon a prosthesis fixinggroove 86 in the prosthesis's axis of insertion, a gap between thesidewall of the fixing projection and the sidewall of the prosthesisfixing groove, on average, is less than about 60μ, about 80μ, about100μ, about 120μ, about 140μ, about 160μ, about 180μ, or about 200μ.Such conditions are difficult to achieve without using a preparationguide device and depending solely on a dental practitioner's handmovement.

As illustrated in FIGS. 57-62, the preparation guide device 100 of oneembodiment allows cutting of anterior lingual surfaces along thecingulum such that the prosthesis can be fixed on two anterior teeth.The preparation guide device 100 includes a tool guide way 120 having anarc shape to guide a burr. In one embodiment, prosthesis fixing grooves86 on the lingual surfaces 70 of anterior teeth are formed along thecingulum by engaging a preparation guide device 100 and cutting teeth asthe burr moves along a tool guide way 120.

The interior walls of prosthesis fixing grooves 86 thus formed have noundercut with respect to the prosthesis's intended axis of insertion. Asshown in FIG. 23E, in one embodiment, the side surfaces 80 of suchprosthesis fixing grooves 86 have sloped surfaces 80 that are consistentwith or are slightly angled compared to the prosthesis axis of insertion76. The angle formed between such sloped interior surfaces 80 and a lineparallel to the prosthesis's axis of insertion, α, ranges from about 0°to about 3°. In one embodiment of the invention, the angle can be about0.3°, about 0.4°, about 0.5°, about 0.6°, about 0.7°, about 0.8°, about0.9°, about 1°, about 1.1°, about 1.2°, about 1.3°, about 1.4°, about1.5°, about 1.7°, about 1.9°, about 2°, about 2.3°, about 2.7°, about3°, about 3.5°, or about 4°. In other embodiments, the angle can bewithin the range of two of the aforementioned numbers. The groovesformed on two teeth have the same axis of insertion.

As shown in FIGS. 23F and 65, fixing projections 58 of the prosthesisare formed such that they can be inserted and fixed within theprosthesis fixing grooves 86. Thus, the projections 58 on both sides ofan artificial tooth protrude in the same direction as the axis ofinsertion of the prosthesis. In one embodiment, the side surfaces of theprojection 58 also have the same or slightly larger sloped anglecompared to that of the side surfaces of the prosthesis fixing grooves86. In one embodiment, the configurations and structures of such fixingprojections, prosthesis fixing grooves, and prosthesis axis of insertionare the same as described below for an embodiment as shown in FIG. 23B.

Each tool guide way 120 of the preparation guide device 100 includes aprojected structure 1102 that extends and protrudes up from a lingualsidewall 110. The projected structure 1102 includes a non-cutting accessway 1202 in the tool guide way 120, which extends to a tool entrance 125located on the lingual side of the projected structure 1102. Thus,unlike in an embodiment where an entrance is located on a sidewall 110,notches are not formed on the sidewalls 110 of the preparation guidedevice 100 of the embodiment, allowing the preparation guide device 100to be firmly engaged. Such configuration with a tool entrance located onthe projected structure that extends up from a sidewall can also beapplied to preparation guide devices for posterior teeth as well as foranterior teeth.

Embodiment as Shown in FIGS. 76-78

As shown in FIGS. 76-78, the preparation guide device 100 according toone embodiment includes tool guide ways 120 that guide burrs to cut twoanterior teeth along the cingulum. Such preparation guide device differsfrom the embodiments shown in FIGS. 57-65 in that a tool hole 124 isconfigured to allow the burr 200 to be inserted top down and in that itprovides an open portion 118 on the bottom of a sidewall 110. Otherbasic configurations of the embodiment are similar to those of otherembodiments, as shown in FIGS. 57-65.

Preparation Guide Device Set for Cutting Teeth

Either one or two preparation guide devices can be used to cut teeth forcrown bridge prosthesis. In an embodiment where two preparation guidedevices are used to cut a single tooth, one of the preparation guidedevices is configured to engage a tooth before any cutting is performed.The other preparation guide device is configured to engage a tooth aftercutting some portions so as to allow cutting of portions that remainuncut after the first cutting process. Thus, the first preparation guidedevice is used to cut portions or the entirety of proximal, occlusal,buccal or lingual surfaces of a tooth. Then, the second preparationguide device is used to cut remaining portions that require additionalcutting after the cutting process using the first preparation guidedevice is completed.

Use of two preparation guide devices is advantageous for maintaining theposition of the preparation guide device while cutting teeth. This is sofor the first preparation guide device because the remaining uncutportions of teeth continue to provide retention force to maintain thepreparation guide device in place. The second preparation guide devicecan continue to obtain retention force from portions that remain uncutand will not be cut during the whole process. In addition, it is lesslikely that a tool guide way of the preparation guide device for cuttingside surfaces and a tool guide way for cutting occlusal surfaces crosseach other, thus preventing the preparation guide device from becomingrelatively large or complicated. Therefore, it is possible to cut teethwithout having any conflict between guide slots for cutting sidesurfaces (buccal, lingual, and proximal surfaces to be more specific)and guide slots for cutting occlusal surfaces. In one embodiment, thepreparation guide device with a tool guide way mainly for cuttinglingual surfaces of a tooth includes a tool guide way for cuttingocclusal surfaces on the cheek side of that tooth (see FIG. 82). Inaddition, another preparation guide device with a tool guide way mainlyfor cutting lingual surface of a tooth includes a tool guide way forcutting occlusal surfaces on the tongue side of that tooth (see FIG.84).

Embodiment as Shown in FIGS. 80-85

FIGS. 80-85 show a pair of preparation guide devices according to oneembodiment of the invention to cut teeth in preparation for engaging acrown and bridge prosthesis 50. The first preparation guide device 1001002, as illustrated in FIGS. 80A, 81, and 82, is configured to cut amolar's occlusal surface on the buccal side and side surfaces on thelingual side and a premolar's occlusal surface on the lingual side andside surfaces on the buccal side from uncut conditions. The secondpreparation guide device 100 1004, as shown in FIG. 80B, is configuredto cut those portions that remain after cutting using the firstpreparation guide device 100 1002. These remaining portions are amolar's occlusal surface on the lingual side and side surfaces on thebuccal side and a premolar's occlusal surface on the buccal side andside surfaces on the lingual side. Referring to FIGS. 81B and 81C, thefirst preparation guide device 100 1002 is first engaged to cut anabutment tooth and is then removed. Subsequently, as shown in FIGS. 83Band 83C, the second preparation guide device 100 1004 is engaged to cutthe abutment tooth 70. The cutting process is completed once the secondpreparation guide device is removed, as shown in FIG. 85. The Crown andbridge prosthesis 50 is subsequently engaged.

Embodiment as Shown in FIGS. 93-104

A pair of preparation guide devices according to one embodiment, asshown in FIGS. 93-104, is configured for cutting teeth in preparationfor engaging a crown prosthesis. The first preparation guide device 1002of the pair, as shown in FIG. 93, is for culling a posterior tooth'sbuccal surface and occlusal surface on the lingual side. An installationsupporting portion 102 of the first preparation guide device 1002includes a mouthpiece-type shape so as to occupy only a small amount ofspace within the mouth.

In order to provide a tool guide way 120 for cutting the buccal surface,a projecting structure 150 extends from the top of the installationsupport portion 102. The interior of such projecting structure 150includes a tool guide way 120, and the tool guide way 120 includes atool hole 124. A projecting wall 152 surrounds the tool guide way 120and the tool hole 124. In addition, to provide a tool guide way 120 forcutting the occlusal surface on the lingual side, a projecting structure160 extends from the side of the installation fixing portion 102. Theinterior of such projecting structure 160 includes a tool guide way 120,and the tool guide way 120 includes a tool hole 124. A projecting wall162 surrounds the tool guide way 120 and the tool hole 124.

Meanwhile, the second preparation guide 1004 for cutting a posteriortooth's lingual surface and occlusal surface on the buccal side alsoincludes a mouthpiece-type shape. Similar to the first preparation guidedevice 1002, the second preparation guide device 1004 includes a firstprojecting structure 150 that extends from the top to provide a toolguide way 120 for cutting the lingual surface and a second projectingstructure 160 that extends from the side to provide a tool guide way 120for culling then occlusal surface on the buccal side. The interior ofthese projecting structures 150, 160 include tool guide ways 120 andtool holes 124. Structures of the tool guide ways 120 and tool holes 124of the preparation guide devices 1002, 1004 can include any of thestructures as described in embodiments above or below.

Embodiment as Shown in FIGS. 86-87

Referring to FIG. 86, the preparation guide device 100 according to oneembodiment of the invention is for cutting labial surfaces of anteriorteeth in preparation for engaging an aesthetic prosthesis 50, such aslaminates. Burrs shown in FIG. 87 can be used in combination with apreparation guide device illustrated in FIG. 86 to cut anterior teeth inpreparation for engaging a laminate prosthesis 50.

Using a Preparation Guide Device for Restoration of Alveolar Bones orother Dental Procedures

Embodiments mentioned above mainly use a preparation guide device fordental procedures to restore lost portions of teeth, such as incombination with bridge prosthesis. The invention, however, is notlimited to such uses. In an embodiment of the invention, a preparationguide device can be used not only to cut teeth but also to attachmaterials to support an alveolar bone when the alveolar bone is damagedor broken. In an embodiment, after cutting an alveolar bone, material tosupport the alveolar bone can be inserted to stabilize a broken portionor to restore a damaged portion. In some embodiments, a preparationguide device can be used to recover a damaged alveolar bone inpreparation for implants.

In some embodiments, procedures for cutting an alveolar bone using apreparation guide device is different from using the same for cuttingteeth in that a support portion of a preparation guide device comes intocontact with an alveolar bone to prevent the preparation guide devicefrom moving. In some embodiments, other aspects of the two proceduresare substantially similar. Similar to embodiments where a preparationguide device is used to cut teeth, in embodiments for cutting analveolar bone, teeth present near the alveolar bone to be cut, if any,can further supply retention force.

In an embodiment of the invention, an alveolar bone can be cut invarious forms by moving a burr along a tool guide way of a preparationguide device, and implants of various forms, such as a mesh, bar or net,can be inserted as needed. Although implant procedures generallycomprise drilling a hole in an alveolar bone in a top-down direction, anembodiment of the invention allows for cutting portions of alveolarbones in various forms as needed while moving a burr along a cuttingguide way of a preparation guide device. Thus, in some embodiments,alveolar bones can be cut in horizontal or curved directions, amongothers.

In addition, in some embodiments, methods of producing a prosthesisdesigned for minimally invasive cutting can be applied to producelaminates for aesthetic purposes and splints to stabilize teeth as well.Also, in some embodiments, crown bridges and crown and bridge prosthesisdesigned for minimally invasive cutting can also be produced using apreparation guide device. Furthermore, in other embodiments, prosthesisto prevent food particles from becoming stuck in between teeth thatrequire only minimally invasive cutting can be produced. For suchpurposes, it is important to cut a minimally invasive amount whilesecuring sufficient retention force by grouping a number of teeth wherefood particles are easily stuck when determining the appropriate axis ofinsertion of the prosthesis. Large amounts of cutting may be required ifthe axis of insertion is not ideal.

Various forms of prosthesis may be produced using a preparation guidedevice of embodiments of the invention. In some embodiments, aprosthesis can be produced before cutting of teeth using a preparationguide device because the prospective cut shape of teeth is predictable.

Furthermore, in some embodiments, a preparation guide device may be usedto insert a pillar comprising both a crown bridge, either inlay oronlay, and endodontic treatment on a tooth. Also, in some embodiments, apreparation guide device may be used to cut remains of a damaged tooththat is not pleasing for aesthetic reasons or is important forstabilization purposes for further dental procedures. In other words, insome embodiments, traditional prosthesis, including splints, laminates,and crown bridges, all remain as viable options in combination with useof a preparation guide device.

Additionally, according to an embodiment of the invention, a prosthesiswith sufficient retention force may be produced by cutting minimallyinvasive amounts of teeth in a shape of a scratch, hole, or groove suchthat the direction of cutting corresponds to the prosthesis's axis ofinsertion. In some embodiments, factors that allow for minimallyinvasive cutting while obtaining sufficient retention force or aestheticvalue can easily be determined. In some embodiments, such factors caninclude, among others, preferable amounts and portions of a tooth to becut and a prosthesis's axis of insertion.

Splint Prosthesis

When an alveolar bone is damaged, teeth that are supported by thedamaged portion of the alveolar bone begin to shake. If a shaking toothis neglected, the alveolar bone is damaged further and the shaking tootheventually falls out. In an embodiment, to prevent such results, ashaking tooth and its adjacent teeth may be connected via a prosthesisto stabilize the shaking tooth. Such prosthesis that connects a shakingtooth and its adjacent teeth is called a splint prosthesis. In anembodiment, if a shaking tooth is fixed via a splint prosthesis, thealveolar bone located below the shaking tooth can be stabilized. In suchembodiments, a stabilized alveolar bone strongly supports the tooth toprevent it from shaking. In addition, in such embodiments where a splintprosthesis fixes a shaking tooth, damage to the alveolar bone can bedelayed, and the alveolar bone can regenerate in some cases as well.

To install a splint prosthesis according to an embodiment of theinvention, damage to the alveolar bone is first diagnosed and teeth toengage the splint prosthesis are determined. In some embodiments, asplint prosthesis is engaged on two or more adjacent teeth. In someembodiments, a rough configuration of the splint prosthesis isdetermined once the teeth to engage the splint prosthesis aredetermined. A splint prosthesis according to an embodiment has astructure that can very strongly unite the teeth it is engaged uponwithout requiring a crown structure. Thus, in some embodiments, such asplint prosthesis does not include any crown structure that requirescutting of whole occlusal surfaces and/or side surfaces. On the otherhand, according an embodiment, appropriate occlusal or side surfaces ofteeth to engage a splint prosthesis is cut using a preparation guidedevice. In some embodiments, a splint prosthesis includes structuresthat tightly fit with the shape of such cut portions so that it isstrongly fixed and bonded.

Splint Prosthesis for Anterior Teeth

Referring to FIGS. 23A, 23B, and 23C, in an embodiment, a splintprosthesis 60 is engaged to fix a shaking tooth 70a with its adjacentteeth. In order to do so, a preparation guide device 100 of anembodiment is engaged on a shaking tooth 70a and its adjacent teeth 70.In some embodiments, the preparation guide device 100 includes a toolguide way 120 per tooth. In some embodiments, such tool guide ways 120generally have an arrow-shaped guide channel. In some embodiments,arrow-shaped prosthesis fixing grooves 86 are formed on each tooth, asillustrated in FIGS. 23B and 23D, as a burr moves along the guidechannels of a tool guide way 120.

FIG. 23D illustrates an embodiment where prosthesis fixing grooves 86are formed on teeth as viewed from the prosthesis's axis of insertion76. Referring to FIG. 23F, a splint prosthesis 51 of an embodiment has asingle body structure which includes one fixing projection 58 per tooth.In some embodiments, such fixing projections protrude and extend in theprosthesis's axis of insertion. In an embodiment, these fixingprojections 58 are inserted into their respective prosthesis fixinggrooves 86 and are cemented such that the splint prosthesis 51 is fixedon teeth (see FIG. 23C). As such, in an embodiment, the shaking tooth70a becomes connected to its adjacent teeth, substantially reducing theshaking which in turn can allow the supporting alveolar bone toregenerate.

In an embodiment as shown in FIGS. 23B, 23D, and 23F, four fixingprojections 58 protrude and extend in the prosthesis's axis of insertion76. FIG. 23D illustrates each prosthesis fixing groove's 86 centerlines87 that depict a burr's axis of rotation (see 201 of FIG. 92 FIGS.92A-92B) as it proceeds along a tool guide way 120. FIG. 23E is across-sectional view of a prosthesis fixing groove 86 of an embodimentcut along a line 88 perpendicular to the centerline 87 at any givenpoint thereof. In such embodiment, it can be seen that all fourprosthesis fixing grooves 86 are sloped inwards along the prosthesis'saxis of insertion 76.

In an embodiment as shown in FIG. 23E, no undercut in the prosthesis'saxis of insertion 76 exists on the interior of prosthesis fixing grooves86. In an embodiment, a sidewall 80 of a prosthesis fixing groove issloped in the prosthesis's axis of insertion. The angle α between suchsidewall 80 and a line 78 parallel to the prosthesis's axis of insertion76 ranges from about 0.3° to about 3°. In an embodiment of theinvention, the angle α is about 0.4°, about 0.5°, about 0.6°, about0.7°, about 0.8°, about 0.9°, about 1°, about 1.1°, about 1.2°, about1.3°, about 1.4°, about 1.5°, about 1.7°, about 1.9°, about 2°, about2.3°, about 2.7°, about 3°, about 3.5°, or about 4°. In otherembodiments, the angle α can be within a range of any of the twoaforementioned numbers. In some embodiments, prosthesis fixing grooveswith a relatively large sloped angle can be easier to insert a fixingprojection into but can have less retention force compared to those witha relatively small sloped angle.

In an embodiment, all four prosthesis fixing grooves 86 as shown in FIG.23B can be cut with a single burr. In some embodiments, when a singleburr cuts all four prosthesis fixing grooves 86 so that the angles ofthe side surfaces of each groove are all equal. In contrast, in otherembodiments, each prosthesis fixing groove 86 can be cut with differentburrs as well.

As shown in FIG. 23, other embodiments can cut teeth according to aprosthesis axis of insertion that is different from that shown in FIG.23F.

Splint Prosthesis for Posterior Teeth

FIGS. 18A, 18B, 18C, and 116-123 show various splint prostheses forposterior teeth. In the embodiments illustrated in FIGS. 18A, 18B, and18C, portions of lingual and proximal surfaces are cut, and a splintprosthesis 51 is engaged. In the illustrated embodiments, the splintprosthesis 51 is engaged to fix a shaking tooth 70a to its adjacentteeth while not damaging the contact points between the two teeth.

In the embodiments as shown in FIGS. 116-118, the preparation guidedevice 100 includes tool guide ways 120 for cutting the lingual, distal,and buccal surfaces of a first molar 70a, the lingual, mesial, andbuccal surfaces of a second molar, and the lingual surfaces of apremolar. In the embodiments shown, the tool guide ways 120 are allconnected such that the burr 200 is inserted top-down in a tool hole 124and moved along the tool guide ways 120 for cutting. Although thecontact point between two molars is cut in this embodiment, retentionforce of the prosthesis is stronger than that of the embodimentillustrated in FIG. 18 because the splint prosthesis 51 is engaged usingboth the lingual and buccal surfaces (which face each other) of eachmolar.

In the embodiments illustrated in FIGS. 119-121, the preparation guidedevice 100 includes tool guide ways 120 for cutting the lingual, distal,and buccal surfaces of a second molar, the lingual and buccal surfacesof a shaking first molar, and the lingual surfaces of a premolar. In theembodiments shown, the tool guide ways 120 are all connected such thatthe burr 200 is inserted in a tool hole 124 located near the premolarand is moved along the tool guide ways 120 for cutting. In thisembodiment, the splint prosthesis 51 can be engaged without damaging thecontact points between two adjacent teeth. In addition, retention forceof the prosthesis is stronger than that of the embodiment illustrated inFIG. 18 because the splint prosthesis 51 is engaged using both thelingual and buccal surfaces of each molar, which face each other.

In one embodiment, as shown in FIGS. 122-123, cutting occurs on thelingual, mesial, and buccal surfaces of a second molar, a portion of thelingual and proximal surfaces of a shaking first molar, and portions ofthe lingual and proximal surfaces of two premolars. In the illustratedembodiment, buccal surfaces of the two premolars and the first molar arenot cut. In order to increase the retention force of the splintprosthesis, the prosthesis is inserted between the first molar's mesialsurface and the second premolar's distal surface that face each other.The prosthesis is further configured to use a second molar's lingual andbuccal surfaces. Thus, although the contact points between a secondpremolar and a first molar and between the two molars can be damagedaccording to this embodiment, the prosthesis can obtain sufficientretention force.

As such, multiple posterior teeth can also be connected using a splintprosthesis, and cutting methods for engaging a posterior splintprosthesis can use a preparation guide device according to the variousembodiments described above.

Dental Procedure Using a Preparation Guide Device

In an embodiment, a dental procedure using the preparation guide deviceincludes the steps of deciding which dental procedures to perform,gathering 3-D shape data about the teeth, selecting a final prospectiveshape with a prosthesis installed, designing the prospective shape ofteeth after cutting, designing or selecting the burr, designing thepreparation guide device, manufacturing the prosthesis, manufacturingthe tool, manufacturing the preparation guide device, cutting the teeth,and installing the prosthesis.

Deciding on Dental Procedure and Collecting Data about Patient's Teeth

Referring to FIG. 105, when a patient visits a dental clinic, the dentalpractitioner examines the patient and decides on the dental procedure tobe performed (S100). In an embodiment of the present invention, thedentist decides on a dental procedure that includes installing aprosthesis in the patient's mouth. At this time, the dental practitionerroughly considers the general configuration of the desired prosthesis.The specifics of the prosthesis are not designed at this point. Forexample, if a dentist decides to use a bridge prosthesis, the dentistcan then decide how many and which teeth to use as abutments.

In an embodiment, then, 3-D data of the patient's teeth shape and/ormouth shape is gathered (S200). In some embodiments, collection of apatient's teeth data can occur before the dental practitioner diagnosesthe patient or decides on a dental procedure. The collection of patientteeth data can occur in various places using various methods. In oneembodiment, the dental practitioner obtains data of the patient's mouthshape using an impression. The dental practitioner or the dental labforms a model of the mouth shape, including the teeth, using theacquired impression. In an embodiment, the shape of this model isscanned and digitalized using a 3-D scanner. In some embodiments, thescanning and/or manufacturing of the model takes place at the dentist'soffice. In other embodiments, the scanning and/or manufacturing takesplace somewhere other than at the dentist's office, such as a lab. Insuch embodiments, the dental practitioner sends the impression to adental lab or other location that performs the scanning and/ormanufacturing. In such embodiments, the dental lab or other locationcreates a model based on the impression and digitalizes the data.Alternatively, in other embodiments, the dental practitioner can use anintra oral scanner to directly scan the oral shape and generate data,and send the data to the dental lab.

In other embodiments, collection of teeth data can occur at a dental labor another place other than the dentist's office. Images can begenerated from the data collected in this way and sent to the dentalpractitioner, and the dental practitioner can determine the dentalprocedure based on these images.

Selecting Prospective Teeth Shape after Prosthesis Installation

In an embodiment, once a dental procedure is determined, data of theoriginal teeth shape is processed to generate data about the prospectiveteeth shape after installation of the prosthesis and to generate acorresponding image. In one embodiment, data and image of theprospective shape are generated for various types of prosthesis. Thegenerated images are sent to the patient. In some embodiments, the oneor more images of prospective shapes of one or more teeth afterinstallation of a dental prosthesis can be delivered to the patient viaemail, text message, mail, courier service, hand-delivery, videoconference, in-person meeting with the patient or an agent thereof,posting on an Internet website, or any appropriate communication meanscurrently existing or to be developed in the future. In an embodiment,the patient checks the images and chooses one of the suggestedprospective shapes. The selected prospective shape becomes the finalteeth shape after the installation of the prosthesis.

Designing Prospective Teeth Shape

In some embodiments, either prior to or after deciding the prospectiveshape of teeth after installation of prosthesis, post-cutting shapes aremodeled and designed for each tooth using the CAD/CAM system (S300). Inan embodiment, during the modeling process, the 3-D images of the teethto be cut are tilted in multiple directions, and one orientation isselected out of the various options. In an embodiment, based on thisorientation, the surface of the teeth to be cut and the axis ofinsertion or orientation of the prosthesis are later decided. In anembodiment, the basic structure of the desired prosthesis orcorresponding teeth cutting conditions or parameters, based on theselected orientation, are inputted into the computer program. In anembodiment, the program allows for designing the prospective teeth shapeon the computer and displays the completed image on the screen. Asillustrated in FIGS. 106-109, in some embodiments, the 3-D data aboutthe prospective shape of teeth after cutting can be rendered ahead oftime and displayed on the monitor as an image. In an embodiment, theportion to be cut and the amount to be cut are determined based on theprospective teeth shape.

Deciding the Axis of Insertion of Prosthesis

According to one embodiment, a dental practitioner selects the axis ofinsertion of the prosthesis which provides sufficient space for fixingthe prosthesis while reducing the amount of teeth cut. Morespecifically, in some embodiments, the CAD/CAM computer program allowstilting of 3-D images of patient teeth in various directions. In someembodiments, the program can further display the portion of the teeth tobe cut for each tilting direction based on preselected parameters. Inone embodiment, such parameters can include the angle between theorientation and cut surface (see angle α in FIGS. 92B and 92C) and thelocation of the lower portion to be cut (e.g., the boundary between gumand teeth). In such embodiments, if one tilts the 3-D image in a certaindirection and transposes a line with an angle of α (including 0 degrees)in reference to that direction on top of that orientation so that theline meets at a point on the boundary of the gum and teeth, such linewill show the side surfaces of teeth that will be cut. If this processis repeated for all points on the boundary of gum and teeth, the amountof teeth cut (volume cut in 3D or depth cut in 2-D) when a particularorientation is selected can be displayed on the screen. Furthermore, byrepeating this process for different orientations of the 3-D image, onecan see how much of the teeth will be cut depending on the axis ofinsertion. Based on this, an axis of insertion can be determined so toobtain a prosthesis with a desired configuration while reducing theamount of teeth cut.

Designing Prosthesis

In an embodiment, once the prospective teeth shape after installing aprosthesis is determined, the prosthesis is designed based on suchprospective shape (S700). As in the embodiment shown in the flowchart ofFIG. 105, designing the prosthesis and deciding the prospective teethshape can occur at the same time, but the present invention is notlimited as such. In other embodiments, the prospective teeth shape canbe determined prior to designing the prosthesis, and vice versa.Moreover, in another embodiment, the prosthesis shape and theprospective teeth shape can be decided at the same time by reviewing howthe shape of one affects the shape of the other. For example, in anembodiment, this can be done by varying the prosthesis shape in view ofthe accompanying retention force and seeing the correspondingprospective teeth shape.

Designing Burr and Guide Device

In an embodiment, after the prospective teeth shape is designed, theburr is designed based on the prospective teeth shape. In designing theburr according to an embodiment, factors to consider include thediameter of the cutting head and the distance between the terminal endof the cutting head and the guide projections (S400). In someembodiments, the design of the burr can also involve using the CAD/CAMsystem. Although a burr is designed in the foregoing embodiment, inother embodiments, several burrs can be manufactured or designedbeforehand and selected appropriately in view of the teeth to be cut.

In an embodiment, after designing the prospective teeth shape anddeciding on a burr, the travel path for the burr is determined using theCAD/CAM system (S500). As in the illustrated embodiments, the design ofthe path can occur at the same as the design of the tool by showing howthey affect one another. In an embodiment, after the path is decided, apreparation guide device that has a tool guide way in the shape of thepath is designed (S600). As shown in FIGS. 100-115, in an embodiment,the design of the preparation guide device can be reviewed as a graphicimage. According to an embodiment, the installation portion of thepreparation guide device is designed using factors such as abutmentteeth data, adjacent teeth data, and gum data. In some embodiments, thenumber and shape of the burr entrance and the number and shape of thecooling water are also designed.

In the above embodiments, the burr is designed first, and thepreparation guide device is designed subsequently, but the design of theburr and the preparation guide device can occur at the same time byconsidering how they affect each other.

Manufacturing Prosthesis, Guide Device, and Burr

In an embodiment, the prosthesis is manufactured according to the designof the prosthesis (S800), and the preparation guide device ismanufactured according to the design of the preparation guide device(S620). In an embodiment, the burr is produced according to the designof the burr (S640).

Sending Prosthesis, Guide Device, and Burr

In an embodiment, once the prosthesis, guide device, and burr aremanufactured, they are sent to the location where the dental procedurewill be performed (S900). In one embodiment, the prosthesis, guidedevice, and burr are sent as a kit in a single box or in a singlecontainer. An embodiment can include an indication in an appropriatelocation on each of the three items to show that the items are for thesame patient. In some embodiments, such indication can be the patient'sname or identification information. In other embodiments, markings canbe placed on the packaging if it is difficult to include the indicationon the product itself. In some embodiments where one patient requiresmultiple guide devices, indications can note for which tooth/teeth thepreparation guide device and burr will be used. Moreover, in someembodiments where two or more guide devices are needed for a singletooth, an indication can denote the order in which the preparation guidedevices should be used.

Cutting Teeth and Installing Prosthesis

In some embodiments, when the patient visits the dentist's office,cutting is performed by installing the preparation guide device insidethe mouth and installing the burr on the hand piece (S1000). Once thecutting is completed, the prepared prosthesis is installed immediatelyon the cut teeth in some embodiments. In some embodiments, cementingprocedures can be used to engage the teeth if necessary.

Using CAD/CAM System

The preparation guide device according to an embodiment of the presentinvention can be designed and manufactured using a CAD/CAM system thatemploys computer design/manufacturing. In some embodiments, if a CAD/CAMsystem is used to manufacture prosthesis, precision can be achieved,costs can be reduced, and the production time can be shortened. In someembodiments, for example, a dental lab can manufacture a preparationguide device using data received about the teeth to be cut or the teethto be used as abutments or using digitalized data of an impression.

More specifically, in some embodiments, numbers regarding the retentionforce needed by a prosthesis are obtained from a database in viewvarious external forces such as chewing force and oral environment.Then, an insertion path for the prosthesis that can meet the requiredretention force with the minimum amount of cutting can be determined.Accordingly, in an embodiment, the shape, amount, and portion to be cutare determined to provide the desired retention force. A preparationguide device is then designed in the CAD system by analyzing such data.A preparation guide device thus prepared can then allow for optimalcutting of teeth. In some embodiments, it is also possible to makevarious prostheses with minimally invasive cutting. In some embodiments,Depending on the oral environment, well-known studies can be used todetermine how much retention force is needed by the abutment teethdepending on the oral environment in order for a prosthesis to be fixed.In other words, some embodiments may employ existing studies that haveanalyzed how well a prosthesis withstands various types of forcesexerted on the teeth, including bite force, tensile force, shear force,and rotational force. In some embodiments, dental practitioners can alsoaccumulate data to use for their own dental procedures.

In an embodiment, a CAD/CAM system can be used to calculate the surfacearea of a tooth to be used as abutment to determine the percentage thatneeds to be cut. Also, in some embodiments, an optimal location that canprovide maximum retention force with minimal invasive cutting can bedetermined. In some embodiments, whether the retention force issufficient can be determine at this time. In some embodiments, data forcalculating the retention force can be inputted into a computer forsimulation. In other embodiments, the CAD/CAM system can be used todetermine the optimal portion and shape for cutting for aestheticprosthesis.

Examples of Designing Guide Device Using CAD/CAM System

FIGS. 127-172 illustrate screen shots which show steps of designing apreparation guide device by processing 3-D (three dimensional) data of atooth using a CAD/CAM computer system in an embodiment. In an embodimentas shown in FIG. 127, a user selects a set of data of teeth among thoselisted on a screen. The selected data set is then processed. Then, in anembodiment as shown in FIG. 128, the computer system displays an imageof a model for a patient's tooth and gum portions corresponding to theselected data set by processing the selected 3-D data set for theselected patient's teeth. In an embodiment, while the selected teethimage is being displayed as shown in FIG. 129, the user clicks a “PrepGuide Wizard” icon for designing a preparation guide device.Subsequently, in an embodiment as shown in FIG. 130, the computer systemdisplays a menu window with design tools.

In an embodiment as shown in FIG. 131, the user clicks an “Align” tabwithin the menu window for determining the axis of prosthesis insertion.Then, in an embodiment as shown in FIG. 132, the computer systemprovides an interactive screen image of the selected teeth so that theuser can see different views of the teeth with different view angles. Inan embodiment, the user can change the viewing angle by dragging acurser with a mouse or by using arrow keys. In response, the computersystem of an embodiment interactively displays a view of the selectedteeth corresponding to the selected viewing angle. In an embodiment,when the user stops the dragging and selects a view of the selectedteeth that is currently displayed, the viewing angle of the image isrecognized a candidate for a prospective axis of prosthesis insertion.

In an embodiment, with respect to each candidate of the prospective axisof prosthesis insertion, the computer system processes the 3-D data toidentify undercut portions and displays the undercut portions usingdifferent colors and/or brightness. Examples of the foregoing processesare shown in FIGS. 133, 134 and 135. The area of the undercut portionsand the depth from the ridge of the survey line to the undercut portioncan vary according to the selection of the axis of prosthesis insertion.Because the cutting portions are generally located between the undercutportions and the occlusal surface, the area and thickness of the cuttingportions can vary according to the locations and/or depth of theundercut portions. In an embodiment, when the user selects anothercandidate for the prospective axis of prosthesis insertion, the computersystem shows the corresponding teeth image, processes the 3-D data,identifies undercut portions, computes the area, locations and thicknessof prospective cutting portions, and stores the resulting data. In anembodiment, the user can check such images and resulting data, andselect one among the candidates as the prospective axis of prosthesisinsertion as shown in FIG. 136. Then, in an embodiment as shown in FIGS.137 and 138, the computer system generates or retrieves data for theselected axis of prosthesis insertion and displays the correspondingtooth image.

In an embodiment as shown in FIG. 139, the user can click a “Pass” tabin the menu window for determining a cutting margin line and select acutting tool as shown in FIG. 140. In some embodiments, the diameter ofthe cutting tool, a distance between the end of the cutting head and theguide bump, the slope of the tapered portion of the cutting head, andother features of the cutting tool can be parameters to be used in thesubsequent steps.

In an embodiment, the user determines the cutting margin line that aterminal end of the cutting tool will follow. First, in an embodiment asshown in FIG. 141, the user selects one location on the lingual surfaceof, for example, the first molar as a starting point. And then, in anembodiment as shown in FIG. 142, the user selects a subsequent locationon the lingual surface of the first molar as a second point, and thecomputer system processes the 3-D data to determine the cutting marginline between the starting point and the second point. In one embodiment,the foregoing work can be done by dragging and pointing a curser with apointing device, such as a mouse. In an embodiment, the computer systemthen stores data regarding the staring starting point and the secondpoint, computes the margin line connecting the staring starting andsecond points, and displays the line on the screen. Subsequently, in anembodiment as shown in FIGS. 143, 144 and 145, the user determines otherportions of the cutting margin line on the lingual surface and theportions of the cutting margin line on the mesial and buccal surfaces.In an embodiment as shown in FIG. 145, the user selects a location onthe buccal surface as an end point to complete designing the cuttingmargin line. FIG. 146 shows the cutting margin line of the first molarin an embodiment.

In an embodiment, the user subsequently changes the viewing angle of thetooth image and determines the cutting margin line of the first premolaras shown in FIGS. 147-153. In an embodiment, once determination of thecutting margin line is completed, as shown in FIG. 154, the computersystem removes the tooth image from the screen and displays only thecutting margin lines and border lines of the tooth model.

In the foregoing embodiments, the user determines the axis of prosthesisinsertion and the cutting margin line. In an alternative embodiment, thecomputer system automatically computes and determines the axis ofprosthesis insertion and the cutting margin line using a pre-preparedalgorithm, and displays the results to the user. In such embodiment,upon receipt of the user's approval, the computer designs thepreparation guide device. If the user rejects the axis and line selectedby the computer in such embodiment, the computer system chooses anotheraxis of prosthesis insertion and cutting margin line and provides themto the user.

In the foregoing embodiments, the locations, thickness and other factorsof the cutting potions are determined according to the determinedcutting margin line. In alternative embodiments, the user provides amaximum cutting depth or thickness, and then, the computer systemdetermines the locations of the cutting portions and the cutting marginlines using a pre-prepared algorithm. In other embodiments, the user canselect the locations and areas of the cutting portions. In oneembodiment, the user selects at least one of the buccal, mesial, lingualand distal surfaces as a surface to be cut, and then, the computersystem determines the cutting margin lines using a pre-installedalgorithm. In some embodiments, the computer system may require only oneparameter among the aforementioned parameters from the user or mayrequire two or more parameters.

In an embodiment, once the cutting margin lines are determined, as shownin FIG. 155, the user clicks a “Body” tab in the menu window fordesigning the body of the preparation guide device. Subsequently, in anembodiment as shown in FIGS. 156 and 157, the computer system generatestwo lines, each of which is parallel to one of the two cutting marginlines. Along the two generated lines, in an embodiment as shown in FIG.158-161, the computer system computes and displays a pathway of thecutting tool. In particular, pathways of a specific structure of thecutting tool, such as the neck portion and/or guide projections, aredisplayed. Then, the tool guide channel is designed. Subsequently, in anembodiment as shown in FIG. 162-169, the computer system generates datafor the body structure and tool guide way structures and displays themon the screen. In an embodiment as shown in FIG. 170-172, the computersystem completes the design of the preparation guide device and displaysit as a solid model on the screen.

No Need for Temporary Crown Prosthesis

According to an embodiment of the present invention, it is not necessaryto install a temporary tooth where a tooth has been cut, as is donecurrently in procedures without using a preparation guide device. Thisreduces the amount of time and manufacturing costs required for suchdental procedures.

No Need for Anesthesia

Currently existing dental procedures that require cutting a large amountof teeth, such as for a crown prosthesis for example, generally involveremoving all of the enamel layer and exposing the dentin layer. If theexposed dentin is further cut, the pulp layer inside can stimulate thenerve, and the patient can experience sharp pains. Therefore, anesthesiais generally required for such procedures. According to embodiments ofthe present invention, however, precise cutting is possible whilecutting only an optimal and minimal amount. Especially in embodimentswhere minimal cutting technology is employed by using a preparationguide device to cut only the enamel layer, the dentin layer remainsunexposed. Accordingly, the patient will experience almost no pain, andsuch dental procedures can be performed without anesthesia. In suchembodiments, the patient does not experience pain after the procedurefor the same reason.

What is claimed is:
 1. A dental preparation guide apparatus in a singlebody, the single body apparatus comprising a lingual sidewall, a buccalsidewall opposing the lingual sidewall, and an occlusal wallinterconnecting the lingual and buccal sidewalls to form the singlebody, wherein the lingual sidewall, the buccal sidewall and the occlusalwall in combination define an interior space in which configured toreceive a tooth comprising a buccal surface, a lingual surface, a mesialsurface, a distal surface and an occlusal surface such that the lingualsurface faces the lingual sidewall, the buccal surface faces the buccalsidewall, and the occlusal surface faces the occlusal wall, theapparatus further comprising a guide channel formed in the single bodyand shaped to receive a cutting tool and guide the cutting tool totravel along a trajectory; the guide channel comprising two opposingchannel surfaces that are substantially parallel to each other andextend along the trajectory such that the cutting tool is constrained bythe two opposing channel surfaces while traveling along the trajectory,the guide channel further comprising at least one anti-tiltingconfiguration formed into at least one of the two channel surfaces andconfigured to engage with the cutting tool for preventing or reducingtilting of the cutting tool in a plane parallel to a movement directionof movement of the cutting tool at a given point of the trajectory whilethe cutting tool travels along the trajectory; wherein the guide channelcomprises a buccal section, a lingual section, and an interconnectingsection interconnecting that interconnects the buccal and lingualsections, which are connected to provide the guide channel as a singleintegrated channel that allows the cutting tool to travel through thebuccal, interconnecting and lingual sections of the guide channelwithout having to remove the cutting tool therefrom; and wherein whenviewing in a direction toward the occlusal wall, the buccal sectionextends generally along the buccal sidewall, and the lingual sectionextends generally along the lingual sidewall.
 2. The apparatus of claim1, wherein the buccal section is configured to cause a portion permit atleast part of the cutting tool to enter into a buccal area of theinterior space between the buccal sidewall and the tooth such that theportion of the cutting tool cuts at least part of the buccal surfacewhile traveling in the buccal section; wherein the lingual section isconfigured to cause the portion permit at least part of the cutting toolto enter into a lingual area of the interior space between the lingualsidewall and the tooth such that the portion of the cutting tool cutcuts at least part of the lingual surface while traveling in the lingualsection; and wherein the interconnecting section is configured to causethe portion permit at least part of the cutting tool to enter into anabutting area of the interior space between the tooth and an immediatelyneighboring tooth such that the portion of the cutting tool cut cuts atleast part of the mesial or distal surface while traveling in theinterconnecting section.
 3. The apparatus of claim 1, wherein whenviewing in the direction toward the occlusal wall, a tangential line ofthe buccal section at a point thereof is parallel to a tangential lineof the lingual section at a point thereof, wherein the at least oneanti-titling anti-tilting configuration comprises a first engagementstructure and a second engagement structure extending along thetrajectory and substantially parallel to each other, the first andsecond engagement structures being configured to engage respectivelywith first and second counterpart structures of the cutting tool,wherein engagement of the first and second engagement structuresrespectively with the first and second counterpart structures is toprevent or reduce tilting of the cutting tool in the plane parallel tothe movement direction and further to prevent disengagement of thecutting tool from the guide channel while traveling along the trajectoryexcept where a port of entry or discharge of the cutting tool isprovided.
 4. The apparatus of claim 3, wherein the guide channel furthercomprises a second interconnecting section that further interconnectsthe buccal and lingual sections to provide the guide channel in the formof a closed loop when viewing in the direction toward the occlusal wall.5. The apparatus of claim 3, wherein the guide channel further comprisesanother section extending from either the buccal section or the lingualsection, wherein when viewing in the direction toward the occlusal wall,a tangential line of the other section at a point thereof is parallel toa tangential line of the interconnecting section at a point thereof. 6.The apparatus of claim 3, wherein the guide channel further comprisesanother section extending from either the buccal section or the lingualsection, wherein when viewing in the direction toward the occlusal wall,a tangential line of the other section at a point thereof is parallel toa tangential line of the interconnecting section at a point thereof,wherein the other section does not interconnect between the buccal andlingual sections, which makes the guide channel in the form of an openloop.
 7. The apparatus of claim 3, wherein the guide channel isconfigured to allow a proximal portion of the cutting tool to passthrough the occlusal wall while allowing a distal portion of the cuttingtool extends into the interior space, wherein each of the first andsecond counterpart structures is in a spherical shape as part of thecutting tool, and wherein each of the first and second engagementstructures is a channel portion of the guide channel configured toaccommodate traveling of the spherical shape therethrough.
 8. A methodof providing a dental restoration kit, the method comprising: providinga first 3D image data representing one or more teeth of a patient beforea desired preparation of the one or more teeth for installing a desireddental prosthesis; before the desired preparation and before making thedesired dental prosthesis, determining an axis of insertion along whichthe desired dental prosthesis should approach the one or more teeth forengaging the desired dental prosthesis with the one or more teeth afterthe desired preparation, wherein the axis of insertion is determinedrelative to the one or more teeth; generating a second 3D image datarepresenting the one or more teeth after to be obtained by the desiredpreparation; producing the dental preparation guide apparatus of claim 3based on the first 3D image data and the second 3D image data, whereinthe interior space of the dental preparation guide apparatus isconfigured to receive the one or more teeth for engagement therewith,wherein the guide channel of the dental preparation guide apparatus isconfigured to guide the cutting tool comprising a burr for cutting atleast part of the one or more teeth for the desired preparation; andproducing the desired prosthesis based on the first 3D image data and 3Dimage data comprising the second 3D image data.
 9. The method of claim8, wherein determining the axis of insertion comprises: processing thefirst 3D image data to orient a 3D image of the one or more teeth inmultiple directions; providing information indicative of undercuts ineach of the multiple directions of orientation of orienting the 3Dimage; and choosing a direction of orientation of the 3D image one ofthe multiple directions as the axis of insertion based on theinformation indicative of the undercuts.
 10. The method of claim 8,wherein generating the second 3D image data comprises: processing thefirst 3D image data together with the input of an area of cutting adesired cutting area and desired cutting depth of cutting, wherein thesingle body apparatus further comprises a port configured to allow theburr at least part of the cutting tool to enter into or discharged fromthe guide channel, wherein the port is located in a portion of thesingle body that corresponds to another tooth received by the interiorspace, wherein the guide channel further comprises a non-cutting accessway interconnecting between the port and one of the buccal section, theinterconnecting section and the lingual section, wherein the non-cuttingaccess way does not cause is configured such that the burr to does notcut the other tooth received by the interior space the one or more teethwhile the cutting tool travels the non-cutting access way.
 11. Themethod of claim 8, wherein generating the second 3D image datacomprises: processing the first 3D image data with thereceiving input ofone or more selected from the group consisting of an orientation of theburr, a diameter of the burr, a length of the burr, tapered shapeinformation of the burr, a position of the burr relative to the one ormore teeth, a distance between a rotational axis of the burr and anexterior surface of the one or more teeth, and a level of the burrrelative to the one or more teeth; and processing the first 3D imagedata together with the input, wherein each of the first and secondcounterpart structures is in a spherical shape as part of the burr, andwherein each of the first and second engagement structures is a channelportion of the guide channel configured to accommodate traveling of thespherical shape therethrough.
 12. The method of claim 8 whereinproducing the desired prosthesis comprises: generating a fourth 3D imagedata of for the desired prosthesis; and making the desired prosthesisusing the fourth 3D image data.
 13. The method of claim 8, furthercomprising providing the burr cutting tool, wherein at least one of thefirst and second counterpart structures is in a spherical shape as partof the burr cutting tool, and wherein at least one of the first andsecond engagement structures is a channel portion of the guide channelconfigured to accommodate traveling of the spherical shape therethrough.14. A method of making devices for dental procedure, comprising:providing a first 3D image data representing one or more teeth of apatient before a desired preparation of the one or more teeth forinstalling a desired dental prosthesis; before the desired preparation,generating a first image illustrating a first prospective shape of theone or more teeth that would exist after installation of a first dentalprosthesis; before the desired preparation, providing the first imagefor the patient's review of the first image; subsequent to the patient'sapproval of the first image and before the desired preparation, causingto make the first dental prosthesis based on image data comprising thefirst image; and subsequent to the patient's approval of the firstimage, making the dental preparation guide apparatus of claim 3 based onthe first 3D image data, wherein the interior space of the dentalpreparation guide apparatus is configured to fit at least part of theone or more teeth, wherein the guide channel of the dental preparationguide apparatus is configured to guide the cutting tool comprising aburr to travel along the trajectory to cut at least part of the one ormore teeth for fitting the first dental prosthesis without the need ofadditional substantial cutting of the one or more teeth.
 15. The methodof claim 14, further comprising: before the desired preparation,generating a second 3D image data representing a prospective, preparedshape of the one or more teeth that would exist after the desiredpreparation thereof, wherein the single body apparatus further comprisesa port configured to allow the burr at least part of the cutting tool toenter into or discharged from the guide channel, wherein the port islocated in a portion of the single body that corresponds to anothertooth received by the interior space, wherein the guide channel furthercomprises a non-cutting access way interconnecting between the port andone of the buccal section, the interconnecting section and the lingualsection, wherein the non-cutting access way does not cause is configuredsuch that the burr to does not cut the other tooth received by theinterior space one or more teeth while the cutting tool travels thenon-cutting access way.
 16. The method of claim 14, further comprising:before the desired preparation, generating a second image illustrating asecond prospective shape of the one or more teeth that would exist afterinstallation of a second dental prosthesis; before the desiredpreparation, providing a plurality of images comprising the first andsecond images for the patient's review; and receiving the patient'sapproval of the first image rather than the second image, wherein thefirst and second prospective shapes differ in at least one selected fromthe group consisting of length, width, surface curvature, embrasure andshading.
 17. The method of claim 14, further comprising: subsequent toproviding the first image and prior to the patient's approval, receivingthe patient's request to modify the first image; changing the firstprospective shape based on the patient's request to modify the firstimage; and providing an a modified first image illustrating the changedfirst prospective shape for the patient's approval.
 18. A method ofdental procedure, comprising: making a the first dental prosthesis and athe preparation guide device in accordance with the method of claim 14,wherein at least one of the first and second counterpart structures isin a spherical shape as part of the burr, and wherein at least one ofthe first and second engagement structures is a channel portion of theguide channel configured to accommodate traveling of the spherical shapetherethrough; and providing the first dental prosthesis and thepreparation guide device to a dental practitioner for preparing at leastpart of the one or more teeth and installing the first dental prosthesisonto the one or more teeth after preparation.
 19. The method of claim18, further comprising: providing the burr along with the first dentalprosthesis and the dental preparation guide apparatus, wherein thedental preparation guide apparatus further comprises a guide grooveformed along the at least one guide channel, wherein the burr comprisesan elongated body with a bump between two ends thereof, wherein theelongated body is configured to fit in the at least one guide channel ofthe preparation guide device and the bump is configured to fit the guidegroove such that the guide channel and the guide groove in combinationposition and orient the burr relative to the one or more teeth in apredetermined manner.
 20. The apparatus of claim 1, wherein the interiorspace defined by the lingual sidewall, the buccal sidewall and theocclusal wall is configured to receive one or more additional teeth,wherein the single body apparatus further comprises a port configured toallow at least part of the cutting tool to enter into or discharged fromthe guide channel, wherein the port is located in a portion of thesingle body that corresponds to one of the one or more additional teeth,wherein the guide channel further comprises a non-cutting access wayinterconnecting between the port and one of the buccal section, theinterconnecting section and the lingual section, wherein the non-cuttingaccess way does not cause is configured such that the cutting tool todoes not cut the tooth or one or more additional teeth.
 21. A method ofpreparing a tooth for dental restoration, the method comprising:providing the apparatus of claim 1 for preparation of a tooth comprisinga buccal surface, a lingual surface, a mesial surface, a distal surfaceand an occlusal surface; engaging the apparatus with the tooth such thatthe tooth is received in the interior space and such that the lingualsurface faces the lingual sidewall, the buccal surface faces the buccalsidewall, and the occlusal surface faces the occlusal wall; insertingthe cutting tool comprising a burr into the guide channel via aninsertion hole; traveling the burr cutting tool along the trajectory ofthe guide channel comprising the buccal section, the lingual section andthe interconnecting section, by which the burr cuts side surface of thetooth comprising such that the cutting tool cuts at least part of thelingual surface, at least part of the buccal surface and at least partof the mesial or distal surface; and wherein during traveling of theburr cutting tool along the trajectory, the burr cutting tool is notremoved disengaged from the guide channel until completion of thecutting side surfaces of the tooth.
 22. The method of claim 21, whereinwhen viewing in the direction toward the occlusal wall, a tangentialline of the buccal section at a point thereof is parallel to atangential line of the lingual section at a point thereof, wherein theat least one anti-titling anti-tilting configuration comprises a firstengagement structure and a second engagement structure extending alongthe trajectory and substantially parallel to each other, the first andsecond engagement structures being configured to engage respectivelywith first and second counterpart structures of the cutting tool,wherein engagement of the first and second engagement structuresrespectively with the first and second counterpart structures is toprevent or reduce tilting of the cutting tool in the plane parallel tothe movement direction and further to prevent disengagement of thecutting tool from the guide channel while traveling along the trajectoryexcept where a port of entry or discharge of the cutting tool isprovided in the guide channel.
 23. The apparatus of claim 1, wherein thecutting tool comprises an inserting structure connected to a dentist'shandpiece, in which and a burr connected to the inserting structure,wherein the guide channel is configured to engage with the cutting toolsuch that the inserting structure is inserted between the two opposingchannel surfaces, wherein the inserting structure comprises at least onecounterpart structure configured to engage with the at least oneanti-tilting feature configuration of the guide channel.
 24. A systemfor dental preparation, comprising: the apparatus of claim 1; a dentalhandpiece comprising an inserting structure, wherein the insertingstructure and a burr constitutes constitute a cutting tool to bereceived by the guide channel of the apparatus; and the insertingstructure comprising at least one counterpart structure configured toengage with the at least one anti-tilting configuration of the guidechannel such that the inserting structure is constrained by the at leastone anti-tilting configuration of the guide channel rather than theburr.
 25. The apparatus of claim 1, wherein the cutting tool comprises aburr and an inserting structure that are connected to a dentist'shandpiece, wherein the inserting structure is inserted between andconstrained by the two opposing channel surfaces of the guide channel,wherein the inserting structure cutting tool comprises at least onecounterpart structure configured to engage with the at least oneanti-tilting configuration of the guide channel.
 26. The apparatus ofclaim 1, wherein the cutting tool comprises a burr and an insertingstructure that are connected to a dentist's handpiece, wherein when thecutting tool is received by the guide channel, the inserting structureis constrained by the guide channel whereas the burr is not directlyconstrained by the guide channel.
 27. A dental preparation guideapparatus in a single body, the single body apparatus comprising alingual sidewall, a buccal sidewall opposing the lingual sidewall, andan occlusal wall interconnecting the lingual and buccal sidewalls toform the single body, wherein the lingual sidewall, the buccal sidewalland the occlusal wall in combination define an interior space in whichconfigured to receive two or more teeth comprising a first tooth and asecond tooth, wherein the lingual sidewall comprises a first lingualsidewall and a second lingual sidewall, the buccal sidewall comprises afirst buccal sidewall and a second buccal sidewall, the occlusal wallcomprises a first occlusal wall and a second occlusal wall; wherein thefirst lingual sidewall and the first buccal sidewall oppose each otherand are configured to sandwich the first tooth when the first and secondteeth are received in the interior space; wherein the second lingualsidewall and the second buccal sidewall oppose each other and areconfigured to sandwich the second tooth when the first and second teethare received in the interior space; wherein the first occlusal wallinterconnecting interconnects between the first lingual sidewall and thefirst buccal sidewall and is configured to overlap the first tooth whenthe first and second teeth are received in the interior space; whereinthe second occlusal wall interconnecting interconnects between thesecond lingual sidewall and the second buccal sidewall and is configuredto overlap the second tooth when the first and second teeth are receivedin the interior space; wherein the apparatus further single bodycomprises a first guide channel formed in the single body through thefirst occlusal wall and shaped to receive a cutting tool and guide forguiding the cutting tool to travel along a first trajectory, the firstguide channel comprising a first engagement structure configured toengage with a first counterpart structure of the cutting tool andfurther configured to prevent disengagement of the cutting tool from thefirst guide channel while traveling along the first trajectory; andwherein the single body further comprises a second guide channel formedin through the second occlusal wall and shaped to receive the cuttingtool or another cutting tool to guide for guiding the same to travelalong the second guide channel a second trajectory.
 28. The apparatus ofclaim 27, wherein the first and second teeth are adjacent with eachother with no tooth therebetween and with no missing tooth therebetween,wherein the first guide channel and the second guide channel areconnected together and form a single connected channel such that thecutting tool received in the first guide channel can travel to thesecond guide channel without having to be removed from the first guidechannel.
 29. The apparatus of claim 27, wherein the first and secondteeth are immediately next to each other with no tooth therebetween andwith no missing tooth therebetween, wherein the first guide channel andthe second guide channel are separate from each other and a portion ofthe single piece body blocks between the first and second guide channelssuch that the cutting tool received in the first guide channel must beremoved from the first guide channel in order to be received in thesecond guide channel, wherein the first guide channel comprises a secondengagement structure configured to engage with a second counterpartstructure of the cutting tool, wherein engagement of the first andsecond engagement structures respectively with the first and secondcounterpart structures is to prevent or reduce tilting of the cuttingtool in the a plane parallel to the a movement direction of the cuttingtool at a given point of the first trajectory while traveling along thefirst trajectory.
 30. The apparatus of claim 27, wherein a missing toothexists between the first and second teeth, wherein the lingual sidewallfurther comprises a third lingual sidewall located between the firstlingual sidewall and the second lingual sidewall; wherein the buccalsidewall further comprises a third buccal sidewall located between thefirst buccal sidewall and the second buccal sidewall; wherein theocclusal wall further comprises a third occlusal wall located betweenthe first occlusal wall and the second occlusal wall; wherein the thirdlingual sidewall, the third buccal sidewall and the third occlusal wallat least partially surrounds a space of the missing tooth when the firstand second teeth are received in the interior space; and wherein thefirst guide channel comprises a second engagement structure configuredto engage with a second counterpart structure of the cutting tool,wherein engagement of the first and second engagement structuresrespectively with the first and second counterpart structures is toprevent or reduce tilting of the cutting tool in the a plane parallel tothe a movement direction of the cutting tool at a given point of thefirst trajectory while traveling along the first trajectory.
 31. Theapparatus of claim 30, wherein the single body comprises a third guidechannel formed in through the third occlusal wall and shaped to receivethe cutting tool or another cutting tool to guide for guiding the sameto travel along the third guide channel a third trajectory, wherein thefirst guide channel and the second guide channel are connected togethervia the third guide channel and form a single connected channel suchthat the cutting tool received in the first guide channel can travel tothe second guide channel without having to be removed from the firstguide channel.
 32. The apparatus of claim 30, wherein the single bodydoes not comprise a guide channel in the third occlusal wall, whereinthe first guide channel and the second guide channel are separate fromeach other and a portion of the third occlusal wall blocks is interposedbetween the first and second guide channels such that the cutting toolreceived in the first guide channel must be removed from the first guidechannel in order to be received in the second guide channel.
 33. Theapparatus of claim 27, wherein a third tooth exist exists between thefirst and second teeth, wherein the lingual sidewall further comprises athird lingual sidewall located between the first lingual sidewall andthe second lingual sidewall; wherein the buccal sidewall furthercomprises a third buccal sidewall located between the first buccalsidewall and the second buccal sidewall; wherein the occlusal wallfurther comprises a third occlusal wall located between the firstocclusal wall and the second occlusal wall; wherein the third lingualsidewall, the third buccal sidewall and the third occlusal wall at leastpartially surrounds the third tooth when the first, second and thirdteeth are received in the interior space; and wherein the first guidechannel comprises a second engagement structure configured to engagewith a second counterpart structure of the cutting tool, whereinengagement of the first and second engagement structures respectivelywith the first and second counterpart structures is to prevent or reducetilting of the cutting tool in the a plane parallel to the a movementdirection of the cutting tool at a given point of the first trajectorywhile traveling along the first trajectory.
 34. The apparatus of claim33, wherein the single body comprises a third guide channel formed inthrough the third occlusal wall and shaped to receive the cutting toolor another cutting tool to guide for guiding the same to travel alongthe third guide channel a third trajectory, wherein the first guidechannel and the second guide channel are connected together via thethird guide channel and form a single connected channel such that thecutting tool received in the first guide channel can travel to thesecond guide channel without having to be removed from the first guidechannel.
 35. The apparatus of claim 27, wherein the first guide channelcomprises a first buccal section, a first lingual section, and a firstinterconnecting section interconnecting the first buccal and firstlingual sections to provide the first guide channel as a singleintegrated channel that allows the cutting tool to travel between thefirst lingual section and the first buccal section without having toremove the cutting tool therefrom, wherein when viewing in a directiontoward the occlusal wall, the first buccal section extends generallyalong the first buccal sidewall, and the first lingual section extendsgenerally along the first lingual sidewall; and wherein the first guidechannel comprises a second engagement structure configured to engagewith a second counterpart structure of the cutting tool, whereinengagement of the first and second engagement structures respectivelywith the first and second counterpart structures is to prevent or reducetilting of the cutting tool in the a plane parallel to the a movementdirection of the cutting tool at a given point of the first trajectorywhile traveling along the first trajectory.
 36. The apparatus of claim35, wherein the first buccal section is configured to cause a portionpermit at least part of the cutting tool to enter into a buccal area ofthe interior space between the first buccal sidewall and the first toothfor cutting at least part of a buccal surface of the first tooth whiletraveling in the first buccal section when the first and second teethare received in the interior space; wherein the first lingual section isconfigured to cause the portion permit at least part of the cutting toolto enter into a lingual area of the interior space and between the firstlingual sidewall and the first tooth for cutting at least part of alingual surface of the first tooth while traveling in the first lingualsection when the first and second teeth are received in the interiorspace; and wherein the first interconnecting section is configured tocause the portion permit at least part of the cutting tool to enter intothe interior space for cutting at least part of a mesial or distalsurface of the first tooth while traveling in the first interconnectingsection when the first and second teeth are received in the interiorspace.
 37. The apparatus of claim 35, wherein when viewing in thedirection toward the occlusal wall, a tangential line of the firstbuccal section at a point thereof is parallel to a tangential line ofthe first lingual section at a point thereof, wherein each of the firstand second counterpart structures is in a spherical shape as part of thecutting tool, and wherein each of the first and second engagementstructures is a channel portion of the first guide channel configured toaccommodate traveling of the spherical shape therethrough.
 38. Theapparatus of claim 35, wherein the first guide channel further comprisesa second interconnecting section that further interconnects the firstbuccal section and the first lingual section to provide the first guidechannel in the form of a closed loop when viewing in the directiontoward the occlusal wall, wherein each of the first and secondcounterpart structures is in a spherical shape as part of the cuttingtool, and wherein each of the first and second engagement structures isa channel portion of the first guide channel configured to accommodatetraveling of the spherical shape therethrough.
 39. The apparatus ofclaim 35, wherein the first guide channel further comprises anothersection extending from either the first buccal section or the firstlingual section, wherein when viewing in the direction toward theocclusal wall, a tangential line of the other section at a point thereofis parallel to a tangential line of the first interconnecting section ata point thereof, wherein the single body apparatus further comprises aport configured to allow at least part of the cutting tool to enter intoor discharged from the first guide channel, wherein the port is locatedin a portion of the single body that corresponds to one of the two ormore teeth received by the interior space, wherein the first guidechannel further comprises a non-cutting access way interconnectingbetween the port and one of the buccal section, the firstinterconnecting section and the lingual section, wherein the non-cuttingaccess way does not cause the cutting tool to cut is configured suchthat the cutting tool does not cut the two or more teeth while travelingthe non-accessing way.
 40. The apparatus of claim 35, wherein the firstguide channel further comprises another section extending from eitherthe first buccal section or the first lingual section, wherein whenviewing in the direction toward the occlusal wall, a tangential line ofthe other section at a point thereof is parallel to a tangential line ofthe first interconnecting section at a point thereof, wherein the othersection does not interconnect between the first buccal section and thefirst lingual section to make such that the first guide channel isprovided in the form of an open loop, wherein the single body apparatusfurther comprises a port configured to allow at least part of thecutting tool to enter into or discharged from the first guide channel,wherein the port is located in a portion of the single body thatcorresponds to one of the two or more teeth received by the interiorspace, wherein the first guide channel further comprises a non-cuttingaccess way interconnecting between the port and one of the buccalsection, the first interconnecting section and the lingual section,wherein the non-cutting access way does not cause the cutting tool to isconfigured such that the cutting tool does not cut the two or more teethwhile traveling the non-access way.
 41. The apparatus of claim 27,wherein the first guide channel comprises two channel surfaces that aresubstantially parallel and opposing surfaces formed in the single bodyeach other, wherein the two channel surfaces are configured to receiveinterpose part of the cutting tool therebetween and to constrain thecutting tool while traveling along the first trajectory.
 42. Theapparatus of claim 41, wherein the cutting tool further comprises aninserting structure connected to a dentist's handpiece, in which whereinthe first guide channel is configured to engage with the cutting toolsuch that the inserting structure is inserted between the two channelsurfaces and constrained by the two channel surfaces while the cuttingtool is traveling along the first trajectory.
 43. A system for dentalpreparation, comprising: the apparatus of claim 41; a cutting toolcomprising an inserting structure connected to a dental handpiece withanand a burr connected to the inserting structure connected to thedental handpiece; and wherein the inserting structure is configured tobe inserted between and constrained by the two channel surfaces of thefirst guide channel.
 44. A method of dental procedure, comprising:providing a dental prosthesis for installing onto one or more teeth of apatient, the one or more teeth comprising a first tooth comprising thatcomprises an occlusal surface, a buccal side, a lingual side, a distalside and a mesial side; providing a preparation guide device in a singlepiece for use in preparing the one or more teeth of the patient forinstalling the dental prosthesis, wherein the preparation guide deviceis custom-made to fit at least part of the one or more teeth andcomprises at least one guide channel configured to guide a cutting tool,wherein the at least one guide channel comprises a first single channelthat the cutting tool can travel along a first trajectory thereof, thefirst single channel comprising a first engagement structure and asecond engagement structure extending along the first trajectory andsubstantially parallel to each other; mounting the preparation guidedevice over the one or more teeth such that the preparation guide devicefit the at least part of the one or more teeth; providing the cuttingtool comprising a burr, the cutting tool further comprising a firstcounterpart structure and a second counterpart structure; engaging thecutting tool with the first single channel such that the first andsecond counterpart structures of the burr engage respectively with thefirst and second engagement structures of the first single channel;moving the burr cutting tool along the first trajectory to cut the firsttooth on such that the burr of the cutting tool contacts and cuts threeor four of the buccal, lingual, distal and mesial sides of the firsttooth without having to remove disengage the burr cutting tool from thefirst single channel of the preparation guide device, which completespreparation of the first tooth for installing the dental prosthesis ontothe first tooth without the need of an additional preparation guidedevice for preparing the first tooth and without the need of anadditional substantial cutting of the first tooth, wherein engagement ofthe first and second engagement structures with the first and secondcounterpart structures prevents or reduces tilting of the burr cuttingtool in a plane parallel to a movement direction of movement of the burcutting tool at a given point of the first trajectory and furtherprevents disengagement of the burr cutting tool from the first singlechannel while the burr cutting tool is traveling along the firsttrajectory except where at a disengagement configuration is provided inthe first single channel; and subsequently installing the dentalprosthesis onto the first tooth so as to surround the three or four ofthe buccal, lingual, distal and mesial sides of the first tooth.
 45. Themethod of claim 44, wherein cutting of the three or four sides leaves atleast a portion of the four sides of the first tooth uncut, wherein theuncut portion comprises a contact point of the first tooth that contactsa neighboring tooth, wherein at least one of the first and secondcounterpart structures is in a spherical shape as part of the cuttingtool, and wherein at least one of the first and second engagementstructures is a channel portion of the first single channel configuredto accommodate traveling of the spherical shape therethrough.
 46. Themethod of claim 44, wherein the first single channel is configured tocut the four of the buccal, lingual, distal and mesial sides of thefirst tooth, wherein cutting of the four sides entirely encircles thefirst tooth when viewing in a direction toward the occlusal surface,wherein the dental prosthesis comprises a ring structure contacting thefour sides of the first tooth that are cut using the first singlechannel, wherein at least one of the first and second counterpartstructures is in a spherical shape as part of the cutting tool, andwherein at least one of the first and second engagement structures is achannel portion of the first single channel configured to accommodatetraveling of the spherical shape therethrough.
 47. The method of claim44, wherein the first single channel is configured to cut the four ofthe buccal, lingual, distal and mesial sides of the first tooth, whereincutting of the four sides does not entirely encircle the first tooth andleaves at least part of one of the four sides uncut when viewing in adirection toward the occlusal surface, wherein the dental prosthesiscomprises a C-shaped structure contacting the four sides of the firsttooth that are cut using the first single channel, wherein the singlepiece preparation guide device further comprises a port configured toallow the burr cutting tool to enter into or discharged from the firstsingle channel, wherein the port is located in a portion of the singlepiece device that corresponds to one of the one or more teeth, whereinthe first single channel further comprises a non-cutting access wayinterconnecting between that extends from the port and one of the buccalsection, the interconnecting section and the lingual section, whereinthe non-cutting access way does not cause the burr to cut the one ormore teeth.
 48. The method of claim 44, wherein the one or more teethcomprise a first tooth and a second tooth, wherein cutting the one ormore teeth comprises cutting the first tooth and then cutting the secondtooth, wherein the preparation guide device is not disconnected from theone or more teeth between cutting the first tooth and cutting the secondtooth, and wherein the first single channel is further configured to cutthe second tooth in addition to cutting the first tooth without havingto remove the burr disengage the cutting tool from the first singlechannel, wherein the single piece preparation guide device furthercomprises a port configured to allow the burr cutting tool to enter intoor discharged from the first single channel, wherein the port is locatedin a portion of the single piece device that corresponds to one of theone or more teeth, wherein the first single channel further comprises anon-cutting access way interconnecting between that extends from theport and one of the buccal section, the interconnecting section and thelingual section, wherein the non-cutting access way does not cause theburr to cut the one or more teeth.
 49. The method of claim 44, whereinthe one or more teeth comprise a first tooth and a second tooth, whereincutting the one or more teeth comprises cutting the first tooth and thencutting the second tooth, wherein the preparation guide device is notdisconnected from the one or more teeth between cutting the first toothand cutting the second tooth, and wherein the at least one channelcomprises a second single channel that is distinct from the first singlechannel and configured to cut the second tooth.
 50. The method of claim44, wherein providing the dental prosthesis comprises receiving thedental prosthesis from a third party or making the dental prosthesisin-house, wherein providing the preparation guide device comprisesreceiving the preparation guide device from a third party or making thepreparation guide device in-house.
 51. The method of claim 44, furthercomprising: causing to provide a 3D image data representing the one ormore teeth of the patient before cutting the first tooth using thepreparation sufficient to install the dental prosthesis guide device,wherein causing to provide the 3D image data comprises at least oneselected from the group consisting of: scanning of the patient's oralfeatures using a 3D scanning device; and taking an impression of thepatient's oral features; producing a 3D model of the patient's oralfeatures from the impression; and scanning the a 3D model representingthe patient's oral features using a 3D scanning device.
 52. The methodof claim 44, wherein the first single channel comprises two channelsurfaces that are substantially parallel and opposing surfaces formed inthe single piece each other such that the cutting tool is constrained bythe two opposing channel surfaces while traveling along the firsttrajectory.
 53. The method of claim 52, wherein the burr is engaged withthe first single channel via cutting tool further comprises an insertingstructure connected to a dentist's handpiece, in which wherein engagingthe cutting tool comprises inserting the inserting structure is insertedbetween the two channel surfaces and such that the inserting structureis constrained by the two opposing channel surfaces while travelingalong the first trajectory.
 54. A dental preparation guide apparatus ina single body, the single body apparatus comprising a lingual sidewall,a buccal sidewall opposing the lingual sidewall, and an occlusal wallinterconnecting the lingual and buccal sidewalls to form the singlebody, wherein the lingual sidewall, the buccal sidewall and the occlusalwall in combination define an interior space in which configured toreceive a tooth comprising a buccal surface, a lingual surface, a mesialsurface, a distal surface and an occlusal surface such that the lingualsurface faces the lingual sidewall, the buccal surface faces the buccalsidewall, and the occlusal surface faces the occlusal wall, wherein thesingle body comprising comprises a first guide channel that is formed inthrough the occlusal wall and shaped to engage with a first cutting toolto guide for guiding the first cutting tool to travel along a firsttrajectory; wherein when viewing in a direction toward the occlusalwall, the first guide channel comprising comprises a section thatextends generally along at least part of the buccal sidewall; whereinthe single body comprising comprises a second guide channel that isformed in through at least one of the buccal and lingual sidewalls andshaped to engage with the first cutting tool or a second cutting tool toguide for guiding the same first or second cutting tool to travel alonga second trajectory; and wherein when viewing in a direction toward thebuccal sidewall, the second guide channel comprises a section thatextends generally along at least part of the occlusal wall, wherein thefirst guide channel comprises two channel surfaces that aresubstantially parallel and opposing each other such that the firstcutting tool is constrained by the two channel surfaces while travelingalong the first trajectory.
 55. The apparatus of claim 54, wherein theocclusal wall comprises an interior surface facing the occlusal surfaceof the tooth when the tooth is received in the interior space, whereinthe second guide channel extends generally along the interior surface ofthe occlusal wall when viewing in the direction toward the buccalsidewall; and wherein the buccal side wall comprises an interior surfacefacing the buccal surface of the tooth when the tooth is received in theinterior space, wherein the first guide channel extends generally alongthe interior surface of the buccal wall when viewing in the directiontoward the occlusal wall is configured to permit a burr portion of thefirst cutting tool to enter into the interior space.
 56. The apparatusof claim 54, wherein the first guide channel further comprises anothersection, which extending generally along at least part of the mesial ordistal surface of the tooth when viewed in the direction toward theocclusal wall, wherein the other section is configured to have permit aburr portion of the first cutting tool pass through the occlusal wallsuch that the first cutting tool extends into the interior space, andfurther such that the first cutting tool cuts one of the mesial anddistal surfaces to cut at least part of the mesial or distal surfacewhen the first cutting tool travels in the other section.
 57. A methodof preparing a tooth for dental restoration, the method comprising:providing the apparatus of claim 54 for preparation of a toothcomprising a buccal surface, a lingual surface, a mesial surface, adistal surface and an occlusal surface; engaging the apparatus with thetooth such that the tooth is received in the interior space and suchthat the lingual surface faces the lingual sidewall, the buccal surfacefaces the buccal sidewall, and the occlusal surface faces the occlusalwall; inserting the first cutting tool comprising a burr into the firstguide channel of the apparatus, whereby a cutting portion such that atleast part of the burr enters into the interior space and between thebuccal sidewall and the tooth; cutting at least part of the buccalsurface of the tooth while traveling the burr as the first cutting tooltravels along the first trajectory of the first guide channel; insertingthe first cutting tool or a second cutting tool comprising a burr intothe second guide channel, whereby a cutting portion such that at leastpart of the burr of the first or second cutting tool enters into theinterior space and between the occlusal wall and the tooth, whereininserting the first or second cutting tool into the second guide channelcan occur either before or after cutting the buccal surface; and cuttingat least part of the buccal occlusal surface of the tooth whiletraveling the burr of as the first or second cutting tool travels alongthe second trajectory of the second guide channel.
 58. The apparatus ofclaim 54, wherein the first guide channel comprises two substantiallyparallel and opposing surfaces formed in the single body such that thefirst cutting tool is constrained by the two opposing surfaces whiletraveling along the first trajectory.
 59. The apparatus of claim 58 54,wherein the first cutting tool is to be engaged with the first guidechannel via is configured to engage with an inserting structureconnected to a dentist's handpiece, in which such that the insertingstructure is inserted between the two channel surfaces and constrainedby the two channel surfaces while the first cutting tool is travelingalong the first trajectory, wherein the first cutting tool comprises theinserting structure and the burr integrated with the insertingstructure.
 60. A system for dental preparation, comprising: theapparatus of claim 5854; a dental handpiece with an inserting structureconnected to the dental handpiece; and wherein the inserting structureis configured to be inserted between the two channel surfaces of thefirst guide channel and constrained by the two channel surfaces whilethe first cutting tool is traveling along the first trajectory.
 61. Adental preparation guide apparatus in a single body, the single bodyapparatus comprising a lingual sidewall, a buccal sidewall opposing thelingual sidewall, and an occlusal wall interconnecting the lingual andbuccal sidewalls to form the single body, wherein the lingual sidewall,the buccal sidewall and the occlusal wall in combination define aninterior space in which configured to receive a tooth comprising abuccal surface, a lingual surface, a mesial surface, a distal surfaceand an occlusal surface such that the lingual surface faces the lingualsidewall, the buccal surface faces the buccal sidewall, and the occlusalsurface faces the occlusal wall, wherein the single body comprises aguide channel formed through at least one of the lingual and buccalsidewalls and shaped to engage with a cutting tool to guide for guidingthe cutting tool to travel along a trajectory, the guide channelcomprising two opposing channel surfaces that are substantially parallelto each other and extending along the trajectory such that the cuttingtool is constrained by the two opposing surfaces while traveling alongthe trajectory; and wherein the guide channel is configured to causepermit a burr portion of the cutting tool to enter into the interiorspace and to be inserted between the occlusal wall and the tooth suchthat the burr portion of the cutting tool cuts at least part of theocclusal surface while traveling in the guide channel along thetrajectory.
 62. The apparatus of claim 61, wherein the guide channelcomprises further comprising a port configured to permit the entry ofthe cutting tool into the guide channel, wherein the port of the guidechannel is formed through the occlusal wall such that the cutting toolenters into the guide channel formed in the at least one of the lingualand buccal sidewalls via the port through the occlusal wall, wherein theguide channel comprises an anti-tilting configuration formed into atleast one of the two channel surfaces and configured to engage with thecutting tool for preventing or reducing tilting of the cutting tool in aplane parallel to a movement direction of movement of the cutting toolat a given point of the trajectory while the cutting tool travels alongthe trajectory.
 63. The apparatus of claim 62, wherein the cutting toolis to be engaged with anti-tilting configuration of the guide channelvia is configured to engage with an inserting structure connected to adentist's handpiece, in which such that the inserting structure isinserted between the two opposing surfaces, wherein the insertingstructure comprises a counterpart structure configured to engage withthe anti-tilting configuration of the guide channel such that theinserting structure is further constrained by the guide channel ratherthan the cutting tool of the guide channel, wherein the cutting toolcomprises the inserting structure and the burr portion integrated withthe inserting structure.
 64. A method of preparing a tooth for dentalrestoration, the method comprising: providing the apparatus of claim 62for preparation of a tooth comprising a buccal surface, a lingualsurface, a mesial surface, a distal surface and an occlusal surface,wherein the anti-titling anti-tilting configuration comprises a firstengagement structure and a second engagement structure extending alongthe trajectory and substantially parallel to each other, the first andsecond engagement structures being configured to engage respectivelywith first and second counterpart structures of the cutting tool,wherein engagement of the first and second engagement structuresrespectively with the first and second counterpart structures is toprevent or reduce tilting of the cutting tool in the plane parallel tothe movement direction and further to prevent disengagement of thecutting tool from the guide channel while traveling along the trajectoryexcept where a port of entry or discharge of the cutting tool isprovided; integrating the apparatus with the tooth such that the toothis received in the interior space and such that the lingual surfacefaces the lingual sidewall, the buccal surface faces the buccalsidewall, and the occlusal surface faces the occlusal wall; engaging theguide channel of the apparatus with the a cutting tool comprising aburr, whereby a cutting portion such that at least part of the burrenters into the interior space and between the occlusal wall and thetooth; and traveling the burr cutting tool along the guide channel whilerunning the burr, thereby cutting such that at least part of theocclusal surface of the tooth is cut.
 65. A method of preparing for adental restoration, the method comprising: providing a first 3D imagedata representing one or more teeth of a patient before a desiredpreparation of the one or more teeth for installing a desired dentalprosthesis; before the desired preparation and before making the desireddental prosthesis, determining an axis of insertion along which thedesired dental prosthesis should approach the one or more teeth forengaging the desired dental prosthesis with the one or more teeth afterthe desired preparation; generating a second 3D image data representingthe one or more teeth to be obtained by the desired preparation;producing a dental preparation guide apparatus based on the first 3Dimage data and the second 3D image data, wherein dental preparationguide apparatus comprises a lingual sidewall, a buccal sidewall opposingthe lingual sidewall, and an occlusal wall interconnecting the lingualand buccal sidewalls to form a single piece body, wherein the lingualsidewall, the buccal sidewall and the occlusal wall in combinationdefine an interior space configured to receive one or more teeth forengagement therewith, wherein the dental preparation guide apparatuscomprises a guide channel formed in the single body and shaped toreceive a cutting tool for cutting at least part of the one or moreteeth for the desired preparation; and producing the desired prosthesisbased on 3D image data comprising the second 3D image data.